CN113067460B

CN113067460B - Switching signal generation circuit, method and direct current converter

Info

Publication number: CN113067460B
Application number: CN202110285837.5A
Authority: CN
Inventors: 施浩; 刘伟
Original assignee: Hefei Macrosilicon Technology Co ltd
Current assignee: Hefei Macrosilicon Technology Co ltd
Priority date: 2021-03-17
Filing date: 2021-03-17
Publication date: 2022-03-08
Anticipated expiration: 2041-03-17
Also published as: CN113067460A

Abstract

The invention provides a switching signal generation circuit, a switching signal generation method and a direct current converter. The switching signal generating circuit comprises a controller, a first output power transistor, a second output power transistor, a first switching circuit, a second switching circuit, a third switching circuit, a fourth switching circuit, a first variable resistance circuit, a second variable resistance circuit, a third variable resistance circuit, a fourth variable resistance circuit and a switching signal end. The invention can solve the problem that the switching signal generating circuit in the existing direct current converter can not select and adjust the on-time and the off-time of the output power transistor according to the actual situation.

Description

Switching signal generation circuit, method and direct current converter

Technical Field

The present invention relates to the field of voltage conversion technologies, and in particular, to a switching signal generation circuit, a switching signal generation method, and a dc converter.

Background

In the direct current converter, when the on-time and the off-time of an output power transistor in a switching signal generation circuit are short, the alternating current loss is low, the system efficiency is high, but the shorter on-time and the shorter off-time can generate noise with larger amplitude on a power supply and the ground; when the on-time and off-time of the output power transistor are long, the noise ratio is small, but the efficiency is low. The switching signal generating circuit in the existing direct current converter cannot select and adjust the on time and the off time of the output power transistor according to actual conditions.

Disclosure of Invention

The invention mainly aims to provide a switching signal generation circuit, a switching signal generation method and a direct current converter, and solves the problem that the switching signal generation circuit in the conventional direct current converter cannot selectively adjust the on-time and the off-time of an output power transistor according to actual conditions.

In order to achieve the above object, the present invention provides a switching signal generating circuit applied to a dc converter, the switching signal generating circuit including a controller, a first output power transistor, a second output power transistor, a first switching circuit, a second switching circuit, a third switching circuit, a fourth switching circuit, a first variable resistance circuit, a second variable resistance circuit, a third variable resistance circuit, a fourth variable resistance circuit, and a switching signal terminal;

the control end of the first switch circuit is electrically connected with a first control end, the first end of the first switch circuit is electrically connected with an input voltage end, and the second end of the first switch circuit is electrically connected with the control electrode of the first output power transistor through the first variable resistance circuit;

a first electrode of the first output power transistor is electrically connected with the input voltage end, and a second electrode of the first output power transistor is electrically connected with the switching signal end;

the control end of the second switching circuit is electrically connected with the second control end, the first end of the second switching circuit is electrically connected with the control electrode of the first output power transistor through the second variable resistance circuit, and the second end of the second switching circuit is electrically connected with the first voltage end;

a control end of the third switch circuit is electrically connected with a third control end, a first end of the third switch circuit is electrically connected with the input voltage end, and a second end of the third switch circuit is electrically connected with a control electrode of the second output power transistor through the third variable resistance circuit;

a first electrode of the second output power transistor is electrically connected with the switching signal end, and a second electrode of the second output power transistor is electrically connected with the first voltage end;

a control end of the fourth switching circuit is electrically connected with the fourth control end, a first end of the fourth switching circuit is electrically connected with a control electrode of the second output power transistor through the fourth variable resistance circuit, and a second end of the fourth switching circuit is electrically connected with the first voltage end;

the controller is electrically connected to the first control terminal, the second control terminal, the third control terminal, the fourth control terminal, the first variable resistance circuit, the second variable resistance circuit, the third variable resistance circuit and the fourth variable resistance circuit, respectively, and is configured to control the first switch circuit to be turned on or off by controlling a potential of the first control terminal after the controller is started to start working, control the second switch circuit to be turned on or off by controlling a potential of the second control terminal, control the third switch circuit to be turned on or off by controlling a potential of the third control terminal, control the fourth switch circuit to be turned on or off by controlling a potential of the fourth control terminal, and control a resistance value of the first variable resistance circuit when the first switch circuit is turned on, and when the second switch circuit is conducted, the resistance value of the second variable resistance circuit is controlled, when the third switch circuit is conducted, the resistance value of the third variable resistance circuit is controlled, and when the fourth switch circuit is conducted, the resistance value of the fourth variable resistance circuit is controlled.

Optionally, the switching signal generating circuit according to at least one embodiment of the present invention further includes a start circuit and a comparison circuit;

the starting circuit is respectively electrically connected with the input voltage end and the controller and is used for controlling the starting of the controller when the voltage value of the input voltage signal provided by the input voltage end is greater than the starting threshold voltage so as to enable the controller to start working;

the comparison circuit is respectively electrically connected with the input voltage end and the controller and is used for comparing the voltage value of the input voltage signal with a switching threshold voltage, providing a first control signal to the controller when the voltage value of the input voltage signal is smaller than the switching threshold voltage, and providing a second control signal to the controller when the voltage value of the input voltage signal is larger than the switching threshold voltage;

the controller is configured to control a resistance value of the first variable resistance circuit to be a first resistance value when the first switch circuit is turned on, control a resistance value of the second variable resistance circuit to be a second resistance value when the second switch circuit is turned on, control a resistance value of the third variable resistance circuit to be a third resistance value when the third switch circuit is turned on, and control a resistance value of the fourth variable resistance circuit to be a fourth resistance value when the fourth switch circuit is turned on, after the controller is controlled by the start circuit to start operating, and when the first control signal is received, the resistance value of the first variable resistance circuit is controlled to be the first resistance value; the controller is further configured to, after being controlled by the start circuit to start operating, control the resistance of the first variable resistance circuit to a fifth resistance value when the first switch circuit is turned on and control the resistance of the second variable resistance circuit to a sixth resistance value when the second switch circuit is turned on, control the resistance of the third variable resistance circuit to a seventh resistance value when the third switch circuit is turned on and control the resistance of the fourth variable resistance circuit to an eighth resistance value when the fourth switch circuit is turned on when the second control signal is received;

the first resistance value is greater than the fifth resistance value, the second resistance value is greater than the sixth resistance value, the third resistance value is greater than the seventh resistance value, and the fourth resistance value is greater than the eighth resistance value.

Optionally, the first output power transistor is a p-type transistor, and the second output power transistor is an n-type transistor.

Optionally, the first switching circuit includes a first switching transistor, and the first variable resistance circuit includes a first resistor and a second resistor;

a control electrode of the first switching transistor is electrically connected with the first control end, a first electrode of the first switching transistor is electrically connected with the input voltage end, and a second electrode of the first switching transistor is electrically connected with a fifth control end;

the fifth control end is electrically connected with the controller;

the controller is used for controlling the fifth control end to be communicated with the first end of the first resistor when receiving the first control signal after the controller is controlled by the starting circuit to start working; the controller is further used for controlling the fifth control end to be communicated with the first end of the second resistor when receiving the second control signal after the controller is controlled by the starting circuit to start working;

the resistance value of the first resistor is a first resistance value, and the resistance value of the second resistor is a fifth resistance value;

the second terminal of the first resistor and the second terminal of the second resistor are both electrically connected to the control electrode of the first output power transistor.

Optionally, the second switching circuit includes a second switching transistor, and the second variable resistance circuit includes a third resistor and a fourth resistor;

a control electrode of the second switching transistor is electrically connected with the second control end, a first electrode of the second switching transistor is electrically connected with a sixth control end, and a second electrode of the second switching transistor is electrically connected with the first voltage end;

the sixth control end is electrically connected with the controller;

the controller is used for controlling the communication between the sixth control end and the first end of the third resistor when receiving the first control signal after the controller is controlled by the starting circuit to start working; the controller is further used for controlling the sixth control end to be communicated with the first end of the fourth resistor when receiving the second control signal after the controller is controlled by the starting circuit to start working;

the resistance value of the third resistor is a second resistance value, and the resistance value of the fourth resistor is a sixth resistance value;

a second terminal of the third resistor and a second terminal of the fourth resistor are both electrically connected to the control electrode of the first output power transistor.

Optionally, the third switching circuit includes a third switching transistor, and the third variable resistance circuit includes a fifth resistor and a sixth resistor;

a control electrode of the third switching transistor is electrically connected with the third control end, a first electrode of the third switching transistor is electrically connected with the input voltage end, and a second electrode of the third switching transistor is electrically connected with a seventh control end;

the seventh control end is electrically connected with the controller;

the controller is used for controlling the seventh control end to be communicated with the first end of the fifth resistor when receiving the first control signal after the controller is controlled by the starting circuit to start working; the controller is further used for controlling the communication between the seventh control end and the first end of the sixth resistor when receiving the second control signal after the controller is controlled by the starting circuit to start working;

the resistance value of the fifth resistor is a third resistance value, and the resistance value of the seventh resistor is a seventh resistance value;

a second terminal of the fifth resistor and a second terminal of the sixth resistor are both electrically connected to the control electrode of the second output power transistor.

Optionally, the fourth switching circuit includes a fourth switching transistor, and the fourth variable resistance circuit includes a seventh resistor and an eighth resistor;

a control electrode of the fourth switching transistor is electrically connected with the fourth control end, a first electrode of the fourth switching transistor is electrically connected with the eighth control end, and a second electrode of the fourth switching transistor is electrically connected with the first voltage end;

the eighth control end is electrically connected with the controller;

the controller is used for controlling the eighth control end to be communicated with the first end of the seventh resistor when receiving the first control signal after the controller is controlled by the starting circuit to start working; the controller is further used for controlling the eighth control end to be communicated with the first end of the eighth resistor when receiving the second control signal after the controller is controlled by the starting circuit to start working;

the resistance value of the seventh resistor is a fourth resistance value, and the resistance value of the eighth resistor is an eighth resistance value;

a second terminal of the seventh resistor and a second terminal of the eighth resistor are both electrically connected to the control electrode of the second output power transistor.

The embodiment of the present invention further provides a switching signal generation method, which is applied to the switching signal generation circuit, and the switching signal generation method includes: after the controller is activated to begin operation,

the controller controls the first switch circuit to be switched on or switched off by controlling the potential of the first control end, controls the second switch circuit to be switched on or switched off by controlling the potential of the second control end, controls the third switch circuit to be switched on or switched off by controlling the potential of the third control end, and controls the fourth switch circuit to be switched on or switched off by controlling the potential of the fourth control end;

when the controller controls the first switch circuit to be conducted, the resistance value of the first variable resistance circuit is controlled; when the controller controls the second switch circuit to be conducted, the resistance value of the second variable resistance circuit is controlled; when the controller controls the third switch circuit to be turned on, controlling the resistance value of the third variable resistance circuit; and when the controller controls the fourth switching circuit to be conducted, controlling the resistance value of the fourth variable resistance circuit.

Optionally, the switching signal generating circuit further includes a start circuit and a comparison circuit; the switching signal generation method further includes:

when the voltage value of the input voltage signal provided by the input voltage end is greater than the starting threshold voltage, the starting circuit controls to start the controller, so that the controller starts to work;

the comparison circuit compares a voltage value of the input voltage signal with a switching threshold voltage, and provides a first control signal to the controller when the voltage value of the input voltage signal is less than the switching threshold voltage, and provides a second control signal to the controller when the voltage value of the input voltage signal is greater than the switching threshold voltage.

Optionally, the method for generating the switching signal specifically includes: after the controller is controlled by the start-up circuit to start operating,

when the controller receives the first control signal and controls the first switch circuit to be conducted, the controller controls the resistance value of the first variable resistance circuit to be a first resistance value; when the controller receives the first control signal and controls the second switch circuit to be conducted, the controller controls the resistance of the second variable resistance circuit to be a second resistance value; when the controller receives the first control signal and controls the third switch circuit to be conducted, the controller controls the resistance of the third variable resistance circuit to be a third resistance value; when the controller receives the first control signal and controls the fourth switch circuit to be conducted, the controller controls the resistance of the fourth variable resistance circuit to be a fourth resistance value;

when the controller receives the second control signal and controls the first switch circuit to be conducted, the controller controls the resistance of the first variable resistance circuit to be a fifth resistance value; when the controller receives the second control signal and controls the second switch circuit to be conducted, the controller controls the resistance of the second variable resistance circuit to be a sixth resistance value; when the controller receives the second control signal and controls the third switch circuit to be conducted, the controller controls the resistance of the third variable resistance circuit to be a seventh resistance value; when the controller receives the second control signal and controls the fourth switch circuit to be conducted, the controller controls the resistance of the fourth variable resistance circuit to be an eighth resistance value;

The embodiment of the invention also provides a direct current converter which comprises the switching signal generating circuit.

The switching signal generating circuit, the method and the dc converter according to the embodiments of the present invention may control the resistance value of the first variable resistance circuit when the first switching circuit is turned on, control the resistance value of the second variable resistance circuit when the second switching circuit is turned on, control the resistance value of the third variable resistance circuit when the third switching circuit is turned on, and control the resistance value of the fourth variable resistance circuit when the fourth switching circuit is turned on, so as to control the rising speed and the falling speed of the switching signal (the switching signal may be a clock signal) provided by the switching signal terminal, after the controller is started to start operating, according to the voltage value of the input voltage signal provided by the input voltage terminal, and when the voltage value of the input voltage signal is greater than the switching threshold voltage and less than the start threshold voltage, the rising speed and the falling speed of the switching signal can be controlled to be slow to reduce noise, and when the voltage value of the input voltage signal is greater than the starting threshold voltage, the rising speed and the falling speed of the switching signal can be controlled to be fast to improve efficiency.

Drawings

Fig. 1 is a block diagram of a switching signal generating circuit according to an embodiment of the present invention;

fig. 2 is a circuit diagram of a switching signal generating circuit according to at least one embodiment of the invention;

fig. 3 is a circuit diagram of a switching signal generating circuit according to at least one embodiment of the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The transistors used in all embodiments of the present invention may be transistors, thin film transistors, or field effect transistors or other devices with the same characteristics. In the embodiment of the present invention, in order to distinguish two poles of the transistor except the control pole, one pole is called a first pole, and the other pole is called a second pole.

In practical operation, when the transistor is a triode, the control electrode may be a base electrode, the first electrode may be a collector electrode, and the second electrode may be an emitter electrode; alternatively, the control electrode may be a base electrode, the first electrode may be an emitter electrode, and the second electrode may be a collector electrode.

In practical operation, when the transistor is a thin film transistor or a field effect transistor, the control electrode may be a gate electrode, the first electrode may be a drain electrode, and the second electrode may be a source electrode; alternatively, the control electrode may be a gate electrode, the first electrode may be a source electrode, and the second electrode may be a drain electrode.

The switching signal generation circuit provided by the embodiment of the invention is applied to a direct current converter and comprises a controller, a first output power transistor, a second output power transistor, a first switching circuit, a second switching circuit, a third switching circuit, a fourth switching circuit, a first variable resistance circuit, a second variable resistance circuit, a third variable resistance circuit, a fourth variable resistance circuit and a switching signal end;

The switching signal generating circuit according to the embodiment of the present invention may control the resistance value of the first variable resistance circuit when the first switching circuit is turned on, control the resistance value of the second variable resistance circuit when the second switching circuit is turned on, control the resistance value of the third variable resistance circuit when the third switching circuit is turned on, control the resistance value of the fourth variable resistance circuit when the fourth switching circuit is turned on, control the rising speed and the falling speed of the switching signal (the switching signal may be a clock signal) provided by the switching signal terminal according to the voltage value of the input voltage signal provided from the input voltage terminal after the controller is started to start operation, control the rising speed and the falling speed of the switching signal to be slow when the voltage value of the input voltage signal is greater than the switching threshold voltage and less than the start threshold voltage, the noise is reduced, and when the voltage value of the input voltage signal is greater than the starting threshold voltage, the rising speed and the falling speed of the switching signal can be controlled to be high, so that the efficiency is improved.

Optionally, the first output power transistor is a p-type transistor, and the second output power transistor is an n-type transistor; but not limited thereto.

Optionally, the first voltage terminal may be a ground terminal, but is not limited thereto.

The switching signal generating circuit according to an embodiment of the present invention is applied to a dc converter, and as shown in fig. 1, the switching signal generating circuit includes a controller 10, a first output power transistor MP1, a second output power transistor MN1, a first switching circuit 11, a second switching circuit 12, a third switching circuit 13, a fourth switching circuit 14, a first variable resistance circuit 21, a second variable resistance circuit 22, a third variable resistance circuit 23, a fourth variable resistance circuit 24, and a switching signal terminal SW;

the control terminal of the first switch circuit 11 is electrically connected to a first control terminal Ct1, the first terminal of the first switch circuit 11 is electrically connected to the input voltage terminal VIN, and the second terminal of the first switch circuit 11 is electrically connected to the gate of the first output power transistor MP1 through the first variable resistor circuit 21;

the source of the first output power transistor MP1 is electrically connected to the input voltage terminal VIN, and the drain of the first output power transistor MP1 is electrically connected to the switch signal terminal SW;

the control terminal of the second switch circuit 12 is electrically connected to a second control terminal Ct2, the first terminal of the second switch circuit 12 is electrically connected to the gate of the first output power transistor MP1 through the second variable resistance circuit 22, and the second terminal of the second switch circuit 12 is electrically connected to a ground terminal GND;

a control terminal of the third switch circuit 13 is electrically connected to a third control terminal Ct3, a first terminal of the third switch circuit 13 is electrically connected to the input voltage terminal VIN, and a second terminal of the third switch circuit 13 is electrically connected to the gate of the second output power transistor MN1 through the third variable resistance circuit 23;

the source of the second output power transistor MN1 is electrically connected to the switch signal terminal SW, and the drain of the second output power transistor MN1 is electrically connected to the ground terminal GND;

a control terminal of the fourth switch circuit 14 is electrically connected to the fourth control terminal Ct4, a first terminal of the fourth switch circuit 14 is electrically connected to the gate of the second output power transistor MN1 through the fourth variable resistor circuit 24, and a second terminal of the fourth switch circuit 14 is electrically connected to the ground terminal GND;

the controller 10 is electrically connected to the first control terminal Ct1, the second control terminal Ct2, the third control terminal Ct3, the fourth control terminal Ct4, the first variable resistance circuit 21, the second variable resistance circuit 22, the third variable resistance circuit 23, and the fourth variable resistance circuit 24, respectively, and is configured to control the first switch circuit 11 to be turned on or off by controlling a potential of the first control terminal Ct1 after being turned on and starts to operate, control the second switch circuit 12 to be turned on or off by controlling a potential of the second control terminal Ct2, control the third switch circuit 13 to be turned on or off by controlling a potential of the third control terminal Ct3, control the fourth control terminal Ct4 to be turned on or off by controlling a potential of the fourth switch circuit 14, and be configured to, when the first switch circuit 11 is turned on, the resistance value of the first variable resistance circuit 21 is controlled, the resistance value of the second variable resistance circuit 22 is controlled when the second switch circuit 12 is turned on, the resistance value of the third variable resistance circuit 23 is controlled when the third switch circuit 13 is turned on, and the resistance value of the fourth variable resistance circuit 24 is controlled when the fourth switch circuit 14 is turned on.

In at least one embodiment of the switching signal generating circuit shown in fig. 1, the MP1 is a PMOS transistor (P-type metal-oxide-semiconductor transistor), and the MN1 is an NMOS transistor (N-type metal-oxide-semiconductor transistor).

In operation of at least one embodiment of the switching signal generating circuit shown in fig. 1, after the control circuit 10 is activated to begin operation,

when the control circuit 10 provides a first off control signal to the first control terminal Ct1 and a second on control signal to the second control signal Ct2, the control circuit 10 may provide a third off control signal to the third control terminal Ct3 and a fourth on control signal to the fourth control terminal Ct4, the first switch circuit 11 controls the gate of VIN and MP1 to be disconnected, and the second switch circuit 12 controls the gate of MP1 to be connected with the gate of MP1 through the second variable resistor circuit 22, so that MP1 is turned on and SW and VIN are connected; the third switch circuit 13 controls the disconnection between VIN and the gate of MN1, the fourth switch circuit 14 controls the connection between the gate of MN1 and the ground GND through the fourth variable resistance circuit 24, at this time, MP1 is turned on, MN1 is turned off, and SW outputs a high voltage signal;

when the control circuit 10 provides a first on control signal to the first control terminal Ct1 and a second off control signal to the second control terminal Ct2, the control circuit 10 may provide a third on control signal to the third control terminal Ct3 and a fourth off control signal to the fourth control terminal Ct 35 4, the first switch circuit 11 controls VIN to be connected between the gates of the first variable resistor circuit 21 and the MP1, and the second switch circuit 12 controls the gate of the MP1 to be disconnected from the gate of the MP1, so that the MP1 is turned off and the SW is disconnected from VIN; the third switch circuit 13 controls the connection between VIN and the gate of MN1 through the third variable resistance circuit 23, the fourth switch circuit 14 controls the disconnection between the gate of MN1 and the ground GND, at this time, MP1 is turned off, MN1 is turned on, and SW outputs a low voltage signal.

When the MP1 is turned on and the MN1 is turned off, the switch signal provided by the SW can be changed from a low voltage signal to a high voltage signal, and the resistance value of the second variable resistance circuit 22 and the resistance value of the fourth variable resistance circuit 24 are controlled and adjusted, so that the rising speed of the switch signal output by the SW can be adjusted;

when the MP1 is turned off and the MN2 is turned on, the switch signal provided by the SW can be changed from a high voltage signal to a low voltage signal, and the resistance value of the first variable resistance circuit 21 and the resistance value of the third variable resistance circuit 23 are controlled and adjusted, so that the falling speed of the switch signal output by the SW can be adjusted.

In at least one embodiment of the present invention, the MP1 and MN1 are power output tubes with relatively large size, and the parasitic capacitance of the gate of MP1 and the parasitic capacitance of the gate of MN1 are relatively large, therefore,

when the resistance accessed by the gate of the MP1 is relatively large, the corresponding charging speed and discharging speed are relatively slow, and when the resistance accessed by the gate of the MN1 is relatively large, the corresponding charging speed and discharging speed are relatively slow, and the rising speed and the falling speed of the potential of the switch signal output by the SW are relatively slow when the potential of the switch signal jumps, that is, the on-time of the MP1 is relatively long with the off-time of the MP1, and the on-time of the MP1 is relatively long with the off-time of the MN1, so that the noise is relatively small, and the amplitude of the noise can be reduced;

when the resistance accessed by the gate of the MP1 is relatively small, the corresponding charging speed and discharging speed are relatively high, and when the resistance accessed by the gate of the MN1 is relatively small, the corresponding charging speed and discharging speed are relatively high, and the rising speed and the falling speed of the potential of the switching signal output by the SW are relatively high when the potential of the switching signal jumps, at this time, the on-time of the MP1 and the off-time of the MP1 are relatively short, and the on-time of the MP1 and the off-time of the MN1 are relatively short, so that the ac loss of the two output power transistors is reduced by adopting the relatively high on-time and off-time, and higher system efficiency is obtained.

The direct current converter comprises the switching signal generating circuit and a filter circuit electrically connected with the switching signal end;

the filter circuit comprises a filter inductor and a filter capacitor which are sequentially connected in series;

the first end of the filter inductor is electrically connected with the switching signal end, the second end of the filter inductor is electrically connected with the first end of the filter capacitor, the second end of the filter capacitor is connected with the direct-current voltage output end, and the direct-current converter is used for converting the input voltage provided by the input voltage end into the direct-current voltage output by the direct-current voltage output end.

In a specific implementation, as shown in fig. 2, on the basis of the embodiment of the switching signal generating circuit shown in fig. 1,

the switching signal generating circuit according to the embodiment of the present invention further includes a start circuit 31 and a comparison circuit 32;

the starting circuit 31 is electrically connected to the input voltage terminal VIN and the controller 10, and is configured to control to start the controller 10 when a voltage value of an input voltage signal provided by the input voltage terminal VIN is greater than a starting threshold voltage, so that the controller 10 starts to operate;

the comparison circuit 32 is electrically connected to the input voltage terminal VIN and the controller 10, and configured to compare a voltage value of the input voltage signal with a switching threshold voltage, and provide a first control signal to the controller 10 when the voltage value of the input voltage signal is smaller than the switching threshold voltage, and provide a second control signal to the controller 10 when the voltage value of the input voltage signal is larger than the switching threshold voltage;

the controller 10 is configured to control the resistance value of the first variable resistance circuit 21 to be a first resistance value when the first switch circuit 11 is turned on, control the resistance value of the second variable resistance circuit 22 to be a second resistance value when the second switch circuit 12 is turned on, control the resistance value of the third variable resistance circuit 23 to be a third resistance value when the third switch circuit 13 is turned on, and control the resistance value of the fourth variable resistance circuit 24 to be a fourth resistance value when the fourth switch circuit 14 is turned on, when the controller receives the first control signal after being controlled by the start circuit 31 to start operating; the controller 10 is further configured to control the resistance of the first variable resistance circuit 21 to be a fifth resistance value when the first switch circuit 11 is turned on, control the resistance of the second variable resistance circuit 22 to be a sixth resistance value when the second switch circuit 12 is turned on, control the resistance of the third variable resistance circuit 23 to be a seventh resistance value when the third switch circuit 13 is turned on, and control the resistance of the fourth variable resistance circuit 24 to be an eighth resistance value when the fourth switch circuit 14 is turned on, when the second control signal is received after being controlled by the start circuit 31 to start operating;

When the embodiment of the switching signal generating circuit shown in fig. 2 of the present invention is in operation, the start circuit 31 controls the controller 10 to start operation when the voltage value of the input voltage signal is greater than the start threshold voltage, and when the voltage value of the input voltage signal is less than the switching threshold voltage, the comparison circuit 32 provides the first control signal to the controller 10 to control the resistance value of the corresponding variable resistance circuit to be a larger resistance value, so as to reduce noise; when the voltage value of the input voltage signal is greater than the switching threshold voltage, the comparison circuit 32 provides a second control signal to the controller 10 to control the resistance value of the corresponding variable resistance circuit to be a smaller resistance value, so that the rising edge and the falling edge of the switching signal are short in time to obtain higher efficiency.

In at least one embodiment of the present invention, the start threshold voltage may be 2V, the switching threshold voltage may be 4V, when the voltage value of the input voltage signal rises from 0V to 2V or more, the start circuit controls the controller 10 to operate, and at this time, the voltage value of the input voltage signal is smaller than 4V, and by selecting the resistance values of the variable resistance circuits, the charge and discharge speed is relatively slow (when the charge and discharge speed is fast, the input voltage signal may generate glitches, and the voltage value of the input voltage signal is easily smaller than 2V, which causes the circuit to be turned off and restarted), so as to reduce noise; when the voltage value of the input voltage signal is larger than 4V, the resistance value of each variable resistance circuit is selected, so that the charging and discharging speed is high, and the charging and discharging efficiency is improved. Optionally, the first output power transistor is a p-type transistor, and the second output power transistor is an n-type transistor; but not limited thereto.

In a specific implementation, the start circuit may include a soft start unit and a UVLO (under voltage lock out) unit, and when a voltage value of the input voltage signal reaches a start threshold voltage, the UVLO unit and the soft start unit control the controller 10 to start to operate, and the dc converter starts to soft start.

In at least one embodiment of the present invention, the first switching circuit includes a first switching transistor, and the first variable resistance circuit includes a first resistor and a second resistor;

the fifth control end is electrically connected with the controller;

In at least one embodiment of the present invention, the second switching circuit includes a second switching transistor, and the second variable resistance circuit includes a third resistor and a fourth resistor;

the sixth control end is electrically connected with the controller;

In at least one embodiment of the present invention, the third switching circuit includes a third switching transistor, and the third variable resistance circuit includes a fifth resistor and a sixth resistor;

the seventh control end is electrically connected with the controller;

In at least one embodiment of the present invention, the fourth switching circuit includes a fourth switching transistor, and the fourth variable resistance circuit includes a seventh resistor and an eighth resistor;

the eighth control end is electrically connected with the controller;

Optionally, the first voltage terminal may be a ground terminal or a low voltage terminal, but is not limited thereto.

As shown in fig. 3, on the basis of the embodiment of the switching signal generating circuit shown in fig. 2, the first switching circuit 11 includes a first switching transistor MP2, and the first variable resistance circuit 21 includes a first resistor R1 and a second resistor R2;

the gate of the first switch transistor MP2 is electrically connected to the first control terminal Ct1, the source of the first switch transistor MP2 is electrically connected to the input voltage terminal VIN, and the drain of the first switch transistor MP2 is electrically connected to the fifth control terminal Ct 5;

the fifth control end Ct5 is electrically connected with the controller 10;

the controller 10 is configured to control the fifth control terminal Ct5 to communicate with the first terminal of the first resistor R1 when receiving the first control signal after being controlled by the start circuit 31 to start operating; the controller 10 is further configured to control the fifth control terminal Ct5 to communicate with the first terminal of the second resistor R2 when receiving the second control signal after being controlled by the start circuit 31 to start operating;

the resistance value of the first resistor R1 is a first resistance value, and the resistance value of the second resistor R2 is a fifth resistance value;

a second terminal of the first resistor R1 and a second terminal of the second resistor R2 are both electrically connected to the gate of the first output power transistor MP 1;

the second switch circuit 12 includes a second switch transistor MN2, and the second variable resistance circuit 22 includes a third resistor R3 and a fourth resistor R4;

the gate of the second switch transistor MN2 is electrically connected to the second control terminal Ct2, the source of the second switch transistor MN2 is electrically connected to the sixth control terminal Ct6, and the drain of the second switch transistor MN2 is electrically connected to the ground terminal GND;

the sixth control end Ct6 is electrically connected with the controller 10;

the controller 10 is configured to control the connection between the sixth control terminal Ct6 and the first terminal of the third resistor R3 when receiving the first control signal after being controlled by the start circuit 31 to start operating; the controller 10 is further configured to control the communication between the sixth control terminal Ct6 and the first terminal of the fourth resistor R4 when receiving the second control signal after being controlled by the start circuit 31 to start operating;

the resistance value of the third resistor R3 is a second resistance value, and the resistance value of the fourth resistor R4 is a sixth resistance value;

a second terminal of the third resistor R3 and a second terminal of the fourth resistor R4 are both electrically connected to a control electrode of the first output power transistor MP 1;

the third switching circuit 13 includes a third switching transistor MP3, and the third variable resistance circuit 23 includes a fifth resistor R5 and a sixth resistor R6;

the gate of the third switching transistor MP3 is electrically connected to the third control terminal Ct3, the source of the third switching transistor MP3 is electrically connected to the input voltage terminal VIN, and the drain of the third switching transistor MP3 is electrically connected to the seventh control terminal Ct 7;

the seventh control end Ct7 is electrically connected with the controller 10;

the controller 10 is configured to control the communication between the seventh control terminal Ct7 and the first terminal of the fifth resistor R5 when receiving the first control signal after being controlled by the start circuit 31 to start operating; the controller 10 is further configured to control the communication between the seventh control terminal Ct7 and the first terminal of the sixth resistor R6 when receiving the second control signal after being controlled by the start circuit 31 to start operating;

the resistance value of the fifth resistor R5 is a third resistance value, and the resistance value of the seventh resistor R7 is a seventh resistance value;

a second terminal of the fifth resistor R5 and a second terminal of the sixth resistor R6 are both electrically connected with the gate of the second output power transistor MN 1;

the fourth switching circuit 14 includes a fourth switching transistor MN3, and the fourth variable resistance circuit 24 includes a seventh resistor R7 and an eighth resistor R8;

the gate of the fourth switching transistor MN3 is electrically connected to the fourth control terminal Ct4, the source of the fourth switching transistor MN3 is electrically connected to the eighth control terminal Ct8, and the drain of the fourth switching transistor MN3 is electrically connected to the ground terminal GND;

the eighth control end Ct8 is electrically connected with the controller 10;

the controller 10 is configured to control the communication between the eighth control terminal Ct8 and the first terminal of the seventh resistor R7 when receiving the first control signal after being controlled by the start circuit 31 to start operating; the controller 10 is further configured to control the communication between the eighth control terminal Ct8 and the first terminal of the eighth resistor R8 when receiving the second control signal after being controlled by the start circuit 31 to start operating;

the resistance value of the seventh resistor R7 is a fourth resistance value, and the resistance value of the eighth resistor R8 is an eighth resistance value;

a second terminal of the seventh resistor R7 and a second terminal of the eighth resistor R8 are both electrically connected to the gate of the second output power transistor MN 1.

In the embodiment shown in fig. 3, MP2 and MP3 are PMOS transistors, and MN2 and MN3 are NMOS transistors.

In the embodiment shown in fig. 3, the first resistance value is greater than the fifth resistance value, the second resistance value is greater than the sixth resistance value, the third resistance value is greater than the seventh resistance value, and the fourth resistance value is greater than the eighth resistance value.

When the embodiment of the switching signal generating circuit shown in fig. 3 of the present invention is in operation, after the starting circuit 31 controls to start the controller 10, so that the controller 10 starts to operate, the comparing circuit 32 compares the voltage value of the input voltage signal with the switching threshold voltage, and provides a first control signal to the controller 10 when the voltage value of the input voltage signal is smaller than the switching threshold voltage, and provides a second control signal to the controller 10 when the voltage value of the input voltage signal is larger than the switching threshold voltage;

MP1 and MN1 are switched on in a time-sharing manner, when MP1 is switched on, MN1 is switched off, SW is communicated with VIN, and SW is disconnected from GND; when the MP1 is turned off and the MN1 is turned on, the SW is disconnected from the VIN, and the SW is communicated with the GND; controlling a voltage value of a direct current voltage signal output by a direct current converter (the direct current converter includes the embodiment of the switching signal generation circuit shown in fig. 3) by controlling a duty ratio of the switching signal output by the SW;

in the embodiment of the present invention, the controller 10 controls the resistance value of each variable resistance circuit to control the rising speed and the falling speed of the switch signal output by the SW.

In operation of the embodiment of the switching signal generating circuit of the present invention as shown in fig. 3, when the comparison circuit 32 provides the first control signal to the controller 10,

when MP2 is turned off, MN2 is turned on, MP3 is turned off, MN3 is turned on, MP1 is turned on, MN1 is turned off, SW and VIN are communicated, SW and GND are turned off, the controller 10 controls the sixth control terminal Ct6 to be communicated with the first end of the third resistor R3, the controller 10 controls the eighth control terminal Ct8 to be communicated with the first end of the seventh resistor R7, so that the gate of MP1 is communicated with GND through R3, and the gate of MN1 is communicated with GND through R7;

when MP2 is turned on, MN2 is turned off, MP3 is turned on, MN3 is turned off, MP1 is turned off, MN1 is turned on, SW and VIN are turned off, SW and GND are communicated, the controller 10 controls the fifth control terminal Ct5 to be communicated with the first end of the first resistor R1, the controller 10 controls the seventh control terminal Ct7 to be communicated with the first end of the fifth resistor R5, so that the gate of MP1 is communicated with VIN through R1, and the gate of MN1 is communicated with VIN through R5;

when the comparison circuit 32 provides a second control signal to the controller 10,

when MP2 is turned off, MN2 is turned on, MP3 is turned off, MN3 is turned on, MP1 is turned on, MN1 is turned off, SW and VIN are communicated, SW and GND are turned off, the controller 10 controls the sixth control terminal Ct6 to be communicated with the first end of the fourth resistor R4, the controller 10 controls the eighth control terminal Ct8 to be communicated with the first end of the eighth resistor R8, so that the gate of MP1 is communicated with GND through R4, and the gate of MN1 is communicated with GND through R8;

when MP2 is turned on, MN2 is turned off, MP3 is turned on, MN3 is turned off, MP1 is turned off, MN1 is turned on, SW and VIN are turned off, SW and GND are communicated, the controller 10 controls the fifth control terminal Ct5 to be communicated with the first end of the second resistor R2, the controller 10 controls the seventh control terminal Ct7 to be communicated with the first end of the sixth resistor R6, so that the gate of MP1 is communicated with VIN through R2, and the gate of MN1 is communicated with VIN through R6.

In the embodiment shown in fig. 3, the resistance value of R1 is greater than the resistance value of R2, the resistance value of R3 is greater than the resistance value of R4, the resistance value of R5 is greater than the resistance value of R6, and the resistance value of R7 is greater than the resistance value of R8.

The switching signal generation method according to the embodiment of the present invention is applied to the switching signal generation circuit, and includes: after the controller is activated to begin operation,

The switching signal generating method according to an embodiment of the present invention may control a resistance value of the first variable resistance circuit when the first switching circuit is turned on, control a resistance value of the second variable resistance circuit when the second switching circuit is turned on, control a resistance value of the third variable resistance circuit when the third switching circuit is turned on, control a resistance value of the fourth variable resistance circuit when the fourth switching circuit is turned on, control a rising speed and a falling speed of a switching signal (the switching signal may be a clock signal) provided by the switching signal terminal according to a voltage value of an input voltage signal provided from an input voltage terminal after a controller is started to start operation, control the rising speed and the falling speed of the switching signal to be slow when the voltage value of the input voltage signal is greater than a switching threshold voltage and less than a start threshold voltage, the noise is reduced, and when the voltage value of the input voltage signal is greater than the starting threshold voltage, the rising speed and the falling speed of the switching signal can be controlled to be high, so that the efficiency is improved.

In specific implementation, when the switching signal generation circuit further comprises a starting circuit and a comparison circuit, the starting circuit controls the controller to start working when the voltage value of the input voltage signal is greater than a starting threshold voltage, and when the voltage value of the input voltage signal is less than a switching threshold voltage, the comparison circuit provides a first control signal to the controller to control the resistance value of the corresponding variable resistance circuit to be a larger resistance value so as to reduce noise; when the voltage value of the input voltage signal is greater than the switching threshold voltage, the comparison circuit provides a second control signal to the controller, and the resistance value of the corresponding variable resistance circuit is controlled to be a smaller resistance value, so that the rising edge and the falling edge of the switching signal are short in time, and higher efficiency is obtained.

In at least one embodiment of the present invention, the method for generating the switching signal may specifically include: after the controller is controlled by the start-up circuit to start operating,

The direct current converter according to the embodiment of the invention includes the switching signal generating circuit.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A switching signal generating circuit is applied to a direct current converter and is characterized by comprising a controller, a first output power transistor, a second output power transistor, a first switching circuit, a second switching circuit, a third switching circuit, a fourth switching circuit, a first variable resistance circuit, a second variable resistance circuit, a third variable resistance circuit, a fourth variable resistance circuit and a switching signal end;

a control end of the fourth switching circuit is electrically connected with a fourth control end, a first end of the fourth switching circuit is electrically connected with a control electrode of the second output power transistor through the fourth variable resistance circuit, and a second end of the fourth switching circuit is electrically connected with the first voltage end;

2. The switching signal generating circuit according to claim 1, further comprising a start-up circuit and a comparison circuit;

3. The switching signal generating circuit according to claim 1 or 2, wherein the first output power transistor is a p-type transistor and the second output power transistor is an n-type transistor.

4. The switching signal generating circuit according to claim 2, wherein the first switching circuit includes a first switching transistor, and the first variable resistance circuit includes a first resistance and a second resistance;

the fifth control end is electrically connected with the controller;

5. The switching signal generating circuit according to claim 2, wherein the second switching circuit includes a second switching transistor, and the second variable resistance circuit includes a third resistance and a fourth resistance;

the sixth control end is electrically connected with the controller;

6. The switching signal generating circuit according to claim 2, wherein the third switching circuit includes a third switching transistor, and the third variable resistance circuit includes a fifth resistance and a sixth resistance;

the seventh control end is electrically connected with the controller;

the resistance value of the fifth resistor is a third resistance value, and the resistance value of the sixth resistor is a seventh resistance value;

7. The switching signal generating circuit according to claim 2, wherein the fourth switching circuit includes a fourth switching transistor, and the fourth variable resistance circuit includes a seventh resistance and an eighth resistance;

the eighth control end is electrically connected with the controller;

8. A switching signal generation method applied to the switching signal generation circuit according to any one of claims 1 to 7, the switching signal generation method comprising: after the controller is activated to begin operation,

9. The switching signal generating method according to claim 8, wherein the switching signal generating circuit further comprises a start-up circuit and a comparison circuit; the switching signal generation method further includes:

10. The switching signal generation method according to claim 9, wherein the switching signal generation method specifically includes: after the controller is controlled by the start-up circuit to start operating,

11. A dc converter comprising the switching signal generating circuit according to any one of claims 1 to 7.