CN202856607U - Control circuit and switching converter - Google Patents
Control circuit and switching converter Download PDFInfo
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- CN202856607U CN202856607U CN 201220459724 CN201220459724U CN202856607U CN 202856607 U CN202856607 U CN 202856607U CN 201220459724 CN201220459724 CN 201220459724 CN 201220459724 U CN201220459724 U CN 201220459724U CN 202856607 U CN202856607 U CN 202856607U
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Abstract
The utility model discloses a control circuit and switch converter, this switch converter include transformer, first switch tube and control circuit, and wherein control circuit has multiplexing input pin, and multiplexing input pin electricity couples to current sampling circuit and voltage sampling circuit in order to receive current sampling signal and voltage sampling signal. The control circuit compares a signal on the multiplexing input pin with a first threshold signal when the first switch tube is switched on and provides a first protection signal according to a comparison result, and the control circuit compares a signal on the multiplexing input pin with a second threshold signal when the first switch tube is switched off and provides a second protection signal according to the comparison result. The utility model discloses a multiple protect function has been realized simultaneously to multiplexing input pin, has better flexibility, has saved the cost simultaneously.
Description
Technical field
Embodiment of the present utility model relates to electronic circuit, especially, relates to a kind of switch converters and control circuit thereof.
Background technology
Now, direct current signal, for example direct voltage or direct current are widely used in many electronic equipments as it provides direct current supply, and these direct current signals derive from switch converters usually.Many switch converters adopt inductor or transformer as energy-storage travelling wave tube, for example in the flyback switching converter, one switching tube is electrically coupled to the armature winding of transformer, control circuit is controlled conducting and the shutoff of this switching tube, the secondary that in transformer, is stored or is passed to transformer that energy is replaced, and then the size of regulation output voltage or output current, reach the purpose of regulation output.
Along with the in recent years development of electronic technology, switch converters is towards highly integrated and high reliability development.Usually, switch converters adopts integrated circuit (IC) as its control circuit.This control IC is when providing the general control function, and for example conducting of output switch control signal control switch pipe and shutoff also needs to have the defencive functions such as overcurrent, overvoltage, excess temperature, to avoid the damage of switch converters.
Usually, control IC has the reception of current sample input pin and has represented the current sampling signal that flows through the switching tube electric current, to be used as current protection; Control IC generally also has the voltage sample input pin and has represented the voltage sampling signal of output voltage with reception, with as voltage protection.Control IC also needs to have the overheat protector function.Traditional overheat protector mainly contains two kinds of ways.A kind of is that temperature detection and defencive function all are integrated in control IC inside.But the shortcoming that temperature detection is integrated in control IC inside is the area that has increased chip, and accuracy of detection is not high, and reliability is inadequate.Because the critical point of overheat protector has been preset in the control IC, flexibility is relatively poor, can not different application requirements be made a change simultaneously.The method of another kind of overheat protector is to increase the temperature sampling input pin, utilizes the external temperature testing circuit to come detected temperatures.But utilize the external temperature testing circuit must additionally increase a chip pin, be unfavorable for controlling the further miniaturization of IC.
The utility model content
In order to solve a previously described problem or a plurality of problem, the utility model proposes control circuit and the switch converters of a kind of easy realization, low cost, high reliability.
A kind of control circuit according to the utility model one embodiment, be used for switch converters, described switch converters comprises the first switching tube, described control circuit has multiplexing input pin, multiplexing input pin received current sampled signal and voltage sampling signal, described control circuit comprises: the sampling selected cell, has first input end, the first output, the second output and control end, wherein first input end is electrically coupled to the multiplexing input pin of control circuit, control end receiving key control signal, the first output is coupled to the multiplexing input pin of control circuit when the first switching tube conducting, and the second output is coupled to the multiplexing input pin of control circuit when the first switching tube turn-offs; The first protected location, have first input end, the second input and output, wherein first input end is electrically coupled to the first output of sampling selected cell, and the second input receives the first threshold signal, and output provides the first guard signal according to current sampling signal and first threshold signal; The second protected location, have first input end, the second input and output, wherein first input end is electrically coupled to the second output of sampling selected cell, and the second input receives the Second Threshold signal, and output provides the second guard signal according to voltage sampling signal and Second Threshold signal; And driving control unit; have first input end, the second input, the 3rd input and output; wherein first input end is electrically coupled to the output of the first protected location; the second input is electrically coupled to the output of the second protected location; the 3rd input receives and drives signal; output is electrically coupled to the control end of the first switching tube with output switch control signal, and driving control unit determines whether the driving signal is exported as switch controlling signal according to the first guard signal and the second guard signal.
In one embodiment, the sampling selected cell comprises the second switch pipe, the second switch pipe has control end, first end and the second end, control end receiving key control signal wherein, first end is electrically coupled to multiplexing input pin, and the second end is electrically coupled to the first output of sampling selected cell or the second output of sampling selected cell under the control of switch controlling signal.
In one embodiment, the second end of second switch pipe is electrically coupled to the first output of sampling selected cell when the first switching tube conducting, and the second end of second switch pipe is electrically coupled to the second output of sampling selected cell when the first switching tube turn-offs.
In one embodiment; when current sampling signal during greater than the first threshold signal driving control unit provide overcurrent protection for switch converters, when voltage sampling signal during greater than the Second Threshold signal driving control unit provide overvoltage protection or overheat protector for switch converters.
In one embodiment; the first protected location comprises the first comparator; the first comparator has in-phase input end, inverting input and output; wherein in-phase input end is coupled to the first output of sampling selected cell; inverting input receives the first threshold signal, and output provides the first guard signal.
In one embodiment; the second protected location comprises the second comparator; the second comparator has in-phase input end, inverting input and output; wherein in-phase input end is coupled to the second output of sampling selected cell; inverting input receives the Second Threshold signal, and output provides the second guard signal.
A kind of switch converters according to the utility model one embodiment comprises: the first switching tube, conducting or shutoff under the control of switch controlling signal; Energy-storage travelling wave tube is electrically coupled to the first switching tube, energy-storage travelling wave tube storage power during the first switching tube conducting, energy-storage travelling wave tube output energy when the first switching tube turn-offs; Current sampling circuit is according to the electric current generation current sampled signal that flows through the first switching tube; Voltage sampling circuit produces voltage sampling signal according to output voltage; And control circuit, be electrically coupled to the control end of the first switching tube so that switch controlling signal to be provided, control circuit has multiplexing input pin, and multiplexing input pin is electrically coupled to current sampling circuit and voltage sampling circuit with received current sampled signal and voltage sampling signal; Wherein said control circuit relatively and according to comparative result provides the first guard signal with the voltage on the multiplexing input pin and first threshold signal when the first switching tube conducting, described control circuit relatively and according to comparative result provides the second guard signal with the voltage on the multiplexing input pin and Second Threshold signal when the first switching tube turn-offs.
In one embodiment, described switch converters comprises above-mentioned control circuit.
In one embodiment, energy-storage travelling wave tube is transformer, and transformer has former limit winding, secondary winding and auxiliary winding, and its limit, Central Plains winding electric is coupled to the first switching tube, voltage sampling circuit is electrically coupled to auxiliary winding, and the voltage at the auxiliary winding two ends of sampling also produces voltage sampling signal.
In one embodiment, voltage sampling circuit comprises: diode, have anode and negative electrode, and its Anodic is electrically coupled to auxiliary winding; Thermistor has first end and the second end, and wherein first end is electrically coupled to the negative electrode of diode; And divider resistance, have first end and the second end, wherein first end is electrically coupled to the second end of thermistor, and the second end is electrically coupled to systematically; Wherein the second end of thermistor is electrically coupled to the multiplexing input pin of control circuit so that voltage sampling signal to be provided.
According to the switch converters that embodiment of the present utility model provides, realized simultaneously multi-protective function by multiplexing input pin, have better flexibility and provide cost savings simultaneously, be beneficial to the miniaturization development of control IC.
Description of drawings
By reading with reference to the accompanying drawings detailed description hereinafter, above-mentioned and other purposes of the utility model execution mode, the feature and advantage easy to understand that will become.In the accompanying drawings, show some embodiments possible of the present utility model in exemplary and nonrestrictive mode, wherein:
Fig. 1 is the circuit block diagram according to the switch converters 100 of the utility model one embodiment;
Fig. 2 is the circuit diagram according to the switch converters 200 of the utility model one embodiment;
Fig. 3 is the circuit diagram according to the protective circuit 300 of the utility model one embodiment;
Fig. 4 is the circuit diagram according to the protective circuit 400 of another embodiment of the utility model;
Fig. 5 is the circuit diagram according to the switch converters 500 of another embodiment of the utility model;
Fig. 6 is the circuit diagram of switch converters 600 of the secondary FEEDBACK CONTROL of the utility model one embodiment; And
Fig. 7 is the internal module Figure 70 0 according to the control chip IC1 shown in Figure 6 of the utility model one embodiment.
In the accompanying drawings, identical or corresponding label is used to represent identical or corresponding element.
Embodiment
The below will describe specific embodiment of the utility model in detail, should be noted that the embodiments described herein only is used for illustrating, and be not limited to the utility model.To in the detailed description of the present utility model, in order to understand better the utility model, a large amount of details has been described below.Yet it will be understood by those skilled in the art that does not have these details, and the utility model can be implemented equally.In order to set forth the utility model clearly, this paper has simplified the detailed description of some concrete structures and function.In addition, the similar 26S Proteasome Structure and Function of having described in detail in certain embodiments repeats no more in other embodiments.Although every term of the present utility model is to describe one by one in conjunction with concrete example embodiment, these terms should not be construed as the demonstration execution mode that is confined to set forth here.Below all as an example of AC/DC (ac/dc conversion) circuit that comprises anti exciting converter example the utility model is described, but those skilled in the art as can be known, the utility model also can be used for any DC/DC (DC/DC conversion) topology, such as BUCK (step-down) circuit, BOOST (boosting) circuit, BUCK-BOOST (liter-step-down) circuit, FLYBACK (anti-sharp) circuit and FORWARD (normal shock) circuit etc.
Fig. 1 is the circuit block diagram according to the switch converters 100 of the utility model one embodiment.As shown in Figure 1, switch converters 100 comprises rectifier bridge 11, input capacitance Cin, transformer T1, the first switching tube M1, diode D1, output capacitance Cout, current sampling circuit 12, voltage sampling circuit 13 and control circuit 14.Rectifier bridge 11 receives an AC-input voltage Vin, and converts thereof into direct voltage.Input capacitance Cin is connected in parallel to the output of rectifier bridge 11, and the end of input capacitance Cin is electrically coupled to an end of the former limit of transformer T1 winding, other end welding system ground.The first switching tube M1 electric coupling is at the other end of the former limit of transformer T1 winding with systematically.The anode of diode D1 is electrically coupled to an end of transformer T1 secondary winding, and the cathodic electricity of diode D1 is coupled to the end of output capacitance Cout, and the other end of output capacitance Cout is electrically coupled to the other end of transformer T1 secondary winding.The voltage at output capacitance Cout two ends is the output voltage V out of switch converters 100.In one embodiment, diode D1 can be replaced by synchronous rectifier.The first switching tube M1 can be any controlled semiconductor switch device, such as metal oxide semiconductor field effect tube (MOSFET), igbt (IGBT) etc.The first switching tube M1 has control end with receiving key control signal Vg, the first switching tube M1 conducting or shutoff under the control of switch controlling signal Vg, thereby the size of regulation output voltage Vout or output current.Transformer T1 storage power when the first switching tube M1 conducting, transformer T1 output energy when the first switching tube M1 turn-offs.
In one embodiment, control circuit 14 comprises protective circuit 140 and driving control unit 144, and wherein protective circuit 140 comprises sampling selected cell 141, the first protected location 142 and the second protected location 143.Sampling selected cell 141 has first input end, the first output 1411, the second output 1412 and control end, and wherein first input end is electrically coupled to the multiplexing input pin PRT of control circuit 14, control end receiving key control signal Vg.The first output 1411 of sampling selected cell 141 is coupled to the multiplexing input pin PRT of control circuit 14 with received current sampled signal Is during the first switching tube M1 conducting; The second output 1412 of sampling selected cell 141 was electrically coupled to the multiplexing input pin PRT of control circuit 14 with receiver voltage sampled signal Vs when the first switching tube M1 turn-offed.The first protected location 142 is electrically coupled to the first output 1411 and the first threshold signal Vth1 of sampling selected cell, and exports the first guard signal Pro1 according to current sampling signal Is and first threshold signal Vth1.In one embodiment; the first protected location 142 is exported the first guard signal Pro1 according to the comparative result of current sampling signal Is and first threshold signal Vth1; as current sampling signal Is during greater than first threshold signal Vth1, the first guard signal Pro1 is effective, for example is high level.In one embodiment, the first guard signal Pro1 represents the overcurrent protection signal.The second protected location 143 is electrically coupled to the second output 1412 and the Second Threshold signal Vth2 of sampling selected cell 141, and exports the second guard signal Pro2 according to voltage sampling signal Vs and Second Threshold signal Vth2.In one embodiment; the second protected location 143 is exported the second guard signal Pro2 according to the comparative result of voltage sampling signal Vs and Second Threshold signal Vth2; as voltage sampling signal Vs during greater than Second Threshold signal Vth2, the second guard signal Pro2 is effective, for example is high level.In one embodiment, the second guard signal Pro2 is such as representing overvoltage protection signal, overheat protector signal etc.Driving control unit 144 receives the first guard signal Pro1, the second guard signal Pro2 and drives signal PWM, and is driving pin Driver output switch control signal Vg.Driving control unit 144 determines whether to enter guard mode according to the first guard signal Pro1 and the second guard signal Pro2, and whether will drive signal PWM and export as switch controlling signal Vg.In one embodiment, when the first guard signal Pro1 and the second guard signal Pro2 are all invalid, for example Pro1=0 and Pro2=0 will drive signal PWM as switch controlling signal Vg output, namely Vg=PWM; When the first guard signal Pro1 or the second guard signal Pro2 were effective, for example Pro1=1 or Pro2=1 entered guard mode, stop to export effective switch controlling signal Vg, Vg=" 0 " for example, thus turn-off the first switching tube M1.
In one embodiment, driving signal PWM can obtain by feedback control loop, and control circuit 14 is controlled conducting and the shutoff of the first switching tube M1 by driving signal PWM, thus the output voltage V out of by-pass cock converter 100.Driving signal PWM for example can obtain by output voltage feedback control loop, average current feedback control loop, transient current feedback control loop or other control loop that is fit to arbitrarily.
Fig. 2 is the circuit diagram according to the switch converters 200 of the utility model one embodiment.Switch converters 200 comprises rectifier bridge, input capacitance Cin, transformer T1, the first switching tube M1, diode D1, output capacitance Cout and control circuit 24.Switch converters 200 also comprises the current sampling circuit that resistor R2 forms.The first switching tube M1 is electrically coupled to systematically by resistor R2.When the first switching tube M1 conducting, the electric current that flows through the first switching tube M1 flows through resistor R2 simultaneously, and the voltage at resistor R2 two ends represents current sampling signal Is.Switch converters 200 also comprises the voltage sampling circuit that is comprised of resistor R1 and resistor R2.Transformer T1 has former limit winding W1, secondary winding W2 and auxiliary winding W3.The voltage at the auxiliary winding W3 two ends of voltage sampling circuit sampling that resistor R1 and resistor R2 form, the first end of resistor R1 is electrically coupled to the end of auxiliary winding W3, the second end of resistor R1 is electrically coupled to the first end of resistor R2, and the other end of auxiliary winding W3 is electrically coupled to systematically.In one embodiment, the end of auxiliary winding W3 is electrically coupled to the first end of resistor R1 by diode D2, and the anode of diode D2 is electrically coupled to the end of auxiliary winding W3, and the cathodic electricity of diode D2 is coupled to the first end of resistor R1.When the first switching tube M1 turn-offed, the voltage at resistor R2 two ends had represented voltage sampling signal Vs.In one embodiment, resistor R1 is temperature-sensitive element, for example negative tempperature coefficient thermistor (NTC) or semistor (PTC), and voltage sampling signal Vs is used as overheat protector.Those skilled in the art can know that voltage sampling signal Vs also can be used for the protection that other is fit to arbitrarily, for example overvoltage protection.In other embodiments, current sampling circuit and voltage sampling circuit also can be realized by capacitance partial pressure circuit or other sample circuit that is fit to arbitrarily.
Voltage on the multiplexing input pin PRT is passed to sampling selected cell 241 through sampling hold circuit 245.Sampling selected cell 241 comprises second switch pipe S1, second switch pipe S1 has control end, first end 1 and the second end 2, control end receiving key control signal Vg wherein, first end 1 is electrically coupled to multiplexing input pin PRT by sampling hold circuit 245, and the second end 2 is electrically coupled to the first output 2411 of sampling selected cell 241 or the second output 2412 of sampling selected cell 241 under the control of switch controlling signal Vg.In one embodiment, when the first switching tube M1 conducting, the voltage on the multiplexing input pin PRT is used for overcurrent protection; When the first switching tube M1 turn-offed, the voltage on the multiplexing input pin PRT was used for overvoltage protection or overheat protector.When switch controlling signal Vg was effective, for example Vg was high level, and the second end 2 of second switch pipe S1 is electrically coupled to the first output 2411 of sampling selected cell 241; When switch controlling signal Vg was invalid, for example Vg was low level, and the second end 2 of second switch pipe S1 is electrically coupled to the second output 2412 of sampling selected cell 241.In one embodiment, second switch pipe S1 is single-pole double-throw switch (SPDT).
The first protected location 242 comprises the first comparator C MP1; the first comparator C MP1 has in-phase input end, inverting input and output; wherein in-phase input end is electrically coupled to the first output 2411 of sampling selected cell 241, and inverting input receives first threshold signal Vth1.When the first switching tube M1 conducting, the voltage on the multiplexing input pin PRT is current sampling signal Is, and current signal Is is passed to the in-phase input end of the first comparator C MP1 through sampling hold circuit 245.In one embodiment, as current sampling signal Is during greater than first threshold signal Vth1, the first guard signal Pro1 is effective, and for example Pro1 is high level, and indicator cock converter 200 needs overcurrent protection.In one embodiment, after current sampling signal Is is greater than first threshold signal Vth1 and certain time, effective the first guard signal Pro1 of the first protected location 242 outputs, indicator cock converter 200 needs overcurrent protection.For example the first protected location 242 comprises that also logical block is coupled between the guard signal Pro1 of the output of the first comparator C MP1 and the output of the first protected location 242; so that when the output of the first comparator C MP1 be high level and keep certain hour after, export effective the first guard signal Pro1.
The second protected location 243 comprises the second comparator C MP2; the second comparator C MP2 has in-phase input end, inverting input and output; wherein in-phase input end is electrically coupled to the first output 2412 of sampling selected cell 241, and inverting input receives Second Threshold signal Vth2.When the first switching tube M1 turn-offed, the voltage on the multiplexing input pin PRT was voltage sampling signal Vs, and voltage sampling signal Vs is passed to the in-phase input end of the second comparator C MP2 through sampling hold circuit 245.In one embodiment, as voltage sampling signal Vs during greater than Second Threshold signal Vth2, the second guard signal Pro2 is effective, and for example pro2 is high level, and the indicator cock converter needs overheat protector or overvoltage protection.In one embodiment, after voltage sampling signal Vs is greater than Second Threshold signal Vth2 and certain time, effective the second guard signal Pro2 of the second protected location 243 outputs, indicator cock converter 200 needs overvoltage protection or overheat protector.For example the second protected location 243 comprises that also logical block is coupled between the guard signal Pro2 of the output of the second comparator C MP2 and the output of the second protected location 243; so that when the output of the second comparator C MP2 be high level and keep certain hour after, export effective the second guard signal Pro2.
In embodiment as shown in Figure 2, driving control unit 244 comprise not gate N1, not gate N2 and with door A3.Receive driving signal PWM with the first input end of door A3; the first guard signal Pro1 process not gate N1 is coupled to the second input with door A3; the second guard signal Pro2 process not gate N2 is coupled to the 3rd input with door A3, with door A3 output switch control signal Vg.When the first guard signal Pro1 and the second guard signal Pro2 are low level; driving control unit 244 will drive signal PWM and export as switch controlling signal Vg; when the first guard signal Pro1 or the second guard signal Pro2 are high level; the switch controlling signal Vg of driving control unit 244 output low levels turn-offs the first switching tube M1.
Fig. 3 is the circuit diagram according to the protective circuit 300 of the utility model one embodiment.Protective circuit 300 provides overcurrent index signal OC and provides overvoltage index signal OV according to voltage sampling signal Vs according to current sampling signal Is, and exports the first guard signal Pro1 and export the second guard signal Pro2 according to overvoltage protection signal OV according to overcurrent index signal OC.Protective circuit 300 comprises second switch pipe S1, lead-edge-blanking unit (Lead Edge Blanking) LEB1, lead-edge-blanking unit LEB2, the first comparator C MP1, the second comparator C MP2, logical circuit 31, logical circuit 32 and sampling hold circuit 33.
Second switch pipe S1 has control end, first end and the second end, control end receiving key control signal Vg wherein, first end is electrically coupled to multiplexing input pin PRT by sampling hold circuit 33, and the second end is electrically coupled to end points 311 or end points 312 under the control of switch controlling signal Vg.When switch controlling signal Vg was effective, for example Vg was high level, and the second end of second switch pipe S1 is electrically coupled to end points 311, and when switch controlling signal Vg was invalid, for example Vg was low level, and the second end of second switch pipe S1 is electrically coupled to end points 312.In one embodiment, second switch pipe S1 is single-pole double-throw switch (SPDT).In one embodiment, the first switching tube M1 conducting of switch converters when switch controlling signal Vg is high level, current sampling signal Is is passed to end points 311 through sampling hold circuit 33, the first switching tube M1 of switch converters turn-offs when switch controlling signal Vg is low level, and voltage sampling signal Vs is passed to end points 312 through sampling hold circuit 33.
Lead-edge-blanking unit LEB1 is coupled to end points 311, and the effect that lead-edge-blanking unit LEB2 is coupled to 312, two lead-edge-blanking unit of end points is and suppresses or shield the rub-out signal that first switching tube M1 switch moment produced because of vibration.In one embodiment, lead-edge-blanking unit LEB1/LEB2 for example can comprise the filter circuit that is comprised of resistance, electric capacity.In another embodiment, lead-edge-blanking unit LEB1/LEB2 for example can comprise the screened circuit that is comprised of switching tube, and within the shielding time, the voltage at end points 311/312 place is not delivered to the in-phase input end of the first comparator C MP1/ the second comparator C MP2.The inverting input of the first comparator C MP1 receives first threshold signal Vth1, output output overcurrent index signal OC.In one embodiment, when the voltage of the first comparator C MP1 in-phase input end during greater than first threshold signal Vth1, overcurrent index signal OC is high level, and switch converters needs overcurrent protection.The inverting input of the second comparator C MP2 receives Second Threshold signal Vth2, output output overvoltage index signal OV.In one embodiment, when the voltage of the second comparator C MP2 in-phase input end during greater than Second Threshold signal Vth2, overvoltage index signal OV is high level, and switch converters needs overvoltage protection.
Fig. 4 is the circuit diagram according to the protective circuit 400 of another embodiment of the utility model.Protective circuit 400 provides overcurrent index signal OC and provides excess temperature index signal OT according to voltage sampling signal Vs according to current sampling signal Is, and exports the first guard signal Pro1 and export the second guard signal Pro2 according to overheat protector signal OT according to overcurrent index signal OC.Similar with protective circuit shown in Figure 3 300, protective circuit 400 comprises second switch pipe S1, lead-edge-blanking unit LEB1, lead-edge-blanking unit LEB2, the first comparator C MP1, the second comparator C MP2, logical circuit 31, logical circuit 32 and sampling hold circuit 33.Simple and clear for narrating, below in detail the part identical with protective circuit 300 is described in detail no longer.
The second comparator C MP2 has in-phase input end, inverting input and output, and wherein in-phase input end is electrically coupled to the output of lead-edge-blanking unit LEB2, and inverting input receives Second Threshold signal Vth2, output output excess temperature index signal OT.In one embodiment, when excess temperature index signal OT was high level, switch converters needed overheat protector.
Fig. 5 is the circuit diagram according to the switch converters 500 of another embodiment of the utility model.Similarly, switch converters 500 comprises rectifier bridge, input capacitance Cin, transformer T1, the first switching tube M1, diode D1, output capacitance Cout and control circuit 24.Compare with the described switch converters 200 of Fig. 2, switch converters 500 also further comprises the filter circuit of electric coupling between current sampling circuit/voltage sampling circuit and multiplexing input pin PRT, and auxiliary power supply voltage generation circuit 61.Switch converters 500 also comprises the filter circuit that is comprised of resistor R3 and capacitor C1.The first end of resistor R3 is electrically coupled to the common port of resistor R2 and the first switching tube M1, and the second end of resistor R3 is electrically coupled to multiplexing input pin PRT.The first end of capacitor C1 is electrically coupled to the second end of resistor R3, and the second end of capacitor C1 is electrically coupled to the other end of resistor R2.The voltage at multiplexing input pin PRT place is the current sampling signal Is through filtering when the first switching tube M1 conducting.When the first switching tube M1 turn-offed, the voltage at multiplexing input pin PRT place was the voltage sampling signal Vs through filtering.In one embodiment, resistor R1 is temperature-sensitive element, for example negative tempperature coefficient thermistor (NTC) or semistor (PTC), and voltage sampling signal Vs is used as overheat protector.Those skilled in the art can know that voltage sampling signal Vs also can be as other protection that is fit to arbitrarily, for example overvoltage protection.
Multiplexing input pin PRT receives the current sampling signal Is through filtering when the first switching tube M1 conducting, and the first protective circuit 242 is exported the first guard signal Pro1 according to current sampling signal Is and first threshold signal Vth1, and overcurrent protection is provided.Multiplexing input pin PRT receives the voltage sampling signal Vs through filtering when the first switching tube M1 turn-offs; the second protective circuit 243 is exported the second guard signal Pro2 according to voltage sampling signal Vs and Second Threshold signal Vth2, and overheat protector or overvoltage protection are provided.
In one embodiment, switch converters 500 also comprises auxiliary power supply voltage generation circuit 61.Auxiliary power supply voltage generation circuit 61 comprises diode D3, resistor R4 and capacitor C2.The anode of diode D3 is electrically coupled to the end of auxiliary winding W3, the end of resistor R4 is electrically coupled to the negative electrode of diode D3, the end that the other end of resistor R4 is electrically coupled to capacitor C2 provides auxiliary power supply voltage, and the other end of capacitor C2 is electrically coupled to systematically.Control circuit 24 receives auxiliary power supply voltage at pin VCC.In one embodiment, auxiliary power supply voltage is as the power logic circuitry voltage of control circuit 24 inside.In one embodiment, when the first switching tube M1 turn-offed, auxiliary winding W3 provided energy by diode D3, resistor R4 and capacitor C2 for auxiliary power supply voltage.
Fig. 6 is the circuit diagram of switch converters 600 of the secondary FEEDBACK CONTROL of the utility model one embodiment.Switch converters 600 describes as an example of the control mode of secondary feedback example.In other embodiments, switch converters 600 also can adopt the control mode of former limit feedback.Switch converters 600 and switch converters shown in Figure 5 500 identical parts adopt identical Reference numeral.Simple and clear for narrating, below in detail the part identical with switch converters 500 is described in detail no longer.
In the embodiment shown in fig. 6, resistor R1 is temperature sensor, and its resistance value changes along with the variation of temperature, and resistor R1 for example is negative tempperature coefficient thermistor (NTC).Resistor R1 also can be other temperature sensor that is fit to arbitrarily.In one embodiment, when the first switching tube M1 conducting, the voltage on the multiplexing input pin PRT is as overcurrent protection, and when the first switching tube M1 turn-offed, the voltage on the multiplexing input pin PRT was as overheat protector.
In this embodiment, control circuit comprises control chip IC1 and capacitor C6.In this embodiment, control chip IC1 comprise multiplexing protection pin PRT, auxiliary power supply voltage pin VCC, drive pin Driver, feedback pin FB, set of frequency pin FSET, pin GND systematically.Capacitor C6 is coupled in set of frequency pin FSET and systematically between the pin GND.In other embodiments, capacitor C6 also can be integrated among the control chip IC1.
Fig. 7 illustrates the internal module Figure 70 0 according to control chip IC1 among Fig. 6.Internal module Figure 70 0 comprises feedback control loop 71, protective circuit 72 and logical circuit 73.
Should be appreciated that the circuit shown in Fig. 6 and Fig. 7 and chip internal structure only are schematic.Those skilled in the art can expect that other feasible mode puts into practice the utility model.And execution mode of the present utility model is not only applicable to the secondary feedback control circuit, but goes for any circuit that comprises a plurality of protected locations.
Above-mentioned specification of the present utility model and enforcement only are illustrated the utility model in an exemplary fashion, and these embodiment are not fully detailed, and are not used in the scope of the present utility model that limits.It all is possible changing and revise for disclosed embodiment, the selectivity embodiment that other are feasible and can be understood by those skilled in the art the equivalent variations of element among the embodiment.Other variations of embodiment disclosed in the utility model and modification do not exceed spirit of the present utility model and protection range.
Claims (10)
1. a control circuit is used for switch converters, and described switch converters comprises the first switching tube, it is characterized in that, described control circuit has multiplexing input pin, multiplexing input pin received current sampled signal and voltage sampling signal, and described control circuit comprises:
The sampling selected cell, have first input end, the first output, the second output and control end, wherein first input end is electrically coupled to the multiplexing input pin of control circuit, control end receiving key control signal, the first output is coupled to the multiplexing input pin of control circuit when the first switching tube conducting, and the second output is coupled to the multiplexing input pin of control circuit when the first switching tube turn-offs;
The first protected location, have first input end, the second input and output, wherein first input end is electrically coupled to the first output of sampling selected cell, and the second input receives the first threshold signal, and output provides the first guard signal according to current sampling signal and first threshold signal;
The second protected location, have first input end, the second input and output, wherein first input end is electrically coupled to the second output of sampling selected cell, and the second input receives the Second Threshold signal, and output provides the second guard signal according to voltage sampling signal and Second Threshold signal; And
Driving control unit; have first input end, the second input, the 3rd input and output; wherein first input end is electrically coupled to the output of the first protected location; the second input is electrically coupled to the output of the second protected location; the 3rd input receives and drives signal; output is electrically coupled to the control end of the first switching tube with output switch control signal, and driving control unit determines whether the driving signal is exported as switch controlling signal according to the first guard signal and the second guard signal.
2. control circuit as claimed in claim 1, it is characterized in that, the sampling selected cell comprises the second switch pipe, the second switch pipe has control end, first end and the second end, control end receiving key control signal wherein, first end is electrically coupled to multiplexing input pin, and the second end is electrically coupled to the first output of sampling selected cell or the second output of sampling selected cell under the control of switch controlling signal.
3. control circuit as claimed in claim 2, it is characterized in that, the second end of second switch pipe is electrically coupled to the first output of sampling selected cell when the first switching tube conducting, and the second end of second switch pipe is electrically coupled to the second output of sampling selected cell when the first switching tube turn-offs.
4. control circuit as claimed in claim 2; it is characterized in that; when current sampling signal during greater than the first threshold signal driving control unit provide overcurrent protection for switch converters, when voltage sampling signal during greater than the Second Threshold signal driving control unit provide overvoltage protection or overheat protector for switch converters.
5. control circuit as claimed in claim 1; it is characterized in that; the first protected location comprises the first comparator; the first comparator has in-phase input end, inverting input and output; wherein in-phase input end is coupled to the first output of sampling selected cell; inverting input receives the first threshold signal, and output provides the first guard signal.
6. control circuit as claimed in claim 1; it is characterized in that; the second protected location comprises the second comparator; the second comparator has in-phase input end, inverting input and output; wherein in-phase input end is coupled to the second output of sampling selected cell; inverting input receives the Second Threshold signal, and output provides the second guard signal.
7. a switch converters is characterized in that, described switch converters comprises:
The first switching tube, conducting or shutoff under the control of switch controlling signal;
Energy-storage travelling wave tube is electrically coupled to the first switching tube, energy-storage travelling wave tube storage power during the first switching tube conducting, energy-storage travelling wave tube output energy when the first switching tube turn-offs;
Current sampling circuit is according to the electric current generation current sampled signal that flows through the first switching tube;
Voltage sampling circuit produces voltage sampling signal according to output voltage; And
Control circuit is electrically coupled to the control end of the first switching tube so that switch controlling signal to be provided, and control circuit has multiplexing input pin, and multiplexing input pin is electrically coupled to current sampling circuit and voltage sampling circuit with received current sampled signal and voltage sampling signal; Wherein
Described control circuit relatively and according to comparative result provides the first guard signal with the voltage on the multiplexing input pin and first threshold signal when the first switching tube conducting, described control circuit relatively and according to comparative result provides the second guard signal with the voltage on the multiplexing input pin and Second Threshold signal when the first switching tube turn-offs.
8. switch converters as claimed in claim 7 is characterized in that, described control circuit is such as each described control circuit in the claim 1 to 6.
9. switch converters as claimed in claim 7, it is characterized in that, wherein energy-storage travelling wave tube is transformer, transformer has former limit winding, secondary winding and auxiliary winding, its limit, Central Plains winding electric is coupled to the first switching tube, voltage sampling circuit is electrically coupled to auxiliary winding, and the voltage at the auxiliary winding two ends of sampling also produces voltage sampling signal.
10. switch converters as claimed in claim 9 is characterized in that, wherein voltage sampling circuit comprises:
Diode has anode and negative electrode, and its Anodic is electrically coupled to auxiliary winding;
Thermistor has first end and the second end, and wherein first end is electrically coupled to the negative electrode of diode; And
Divider resistance has first end and the second end, and wherein first end is electrically coupled to the second end of thermistor, and the second end is electrically coupled to systematically; Wherein
The second end of thermistor is electrically coupled to the multiplexing input pin of control circuit so that voltage sampling signal to be provided.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201220459724 CN202856607U (en) | 2012-09-11 | 2012-09-11 | Control circuit and switching converter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220459724 CN202856607U (en) | 2012-09-11 | 2012-09-11 | Control circuit and switching converter |
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| CN202856607U true CN202856607U (en) | 2013-04-03 |
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| CN 201220459724 Expired - Fee Related CN202856607U (en) | 2012-09-11 | 2012-09-11 | Control circuit and switching converter |
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| CN102820764A (en) * | 2012-09-11 | 2012-12-12 | 成都芯源***有限公司 | control circuit, switching converter and control method thereof |
| CN103809059A (en) * | 2014-01-29 | 2014-05-21 | 浙江网新技术有限公司 | Signal detection method and device |
| CN103887984A (en) * | 2014-03-28 | 2014-06-25 | 矽力杰半导体技术(杭州)有限公司 | Isolating converter and switching power supply comprising same |
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| CN102820764A (en) * | 2012-09-11 | 2012-12-12 | 成都芯源***有限公司 | control circuit, switching converter and control method thereof |
| CN103809059A (en) * | 2014-01-29 | 2014-05-21 | 浙江网新技术有限公司 | Signal detection method and device |
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| CN103887984A (en) * | 2014-03-28 | 2014-06-25 | 矽力杰半导体技术(杭州)有限公司 | Isolating converter and switching power supply comprising same |
| CN105572528B (en) * | 2014-11-04 | 2020-01-07 | 意法半导体股份有限公司 | Detection circuit, related active discharge circuit, integrated circuit and method |
| US10345348B2 (en) | 2014-11-04 | 2019-07-09 | Stmicroelectronics S.R.L. | Detection circuit for an active discharge circuit of an X-capacitor, related active discharge circuit, integrated circuit and method |
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| CN108153366A (en) * | 2018-02-27 | 2018-06-12 | 上海灿瑞科技股份有限公司 | A kind of overvoltage crowbar |
| CN110601533A (en) * | 2019-09-19 | 2019-12-20 | 厦门市必易微电子技术有限公司 | Control chip, control circuit, power supply circuit and control method |
| CN112134466A (en) * | 2020-09-09 | 2020-12-25 | 深圳市必易微电子股份有限公司 | Primary side control circuit, power converter and control method thereof |
| CN113676053A (en) * | 2021-07-09 | 2021-11-19 | 深圳市必易微电子股份有限公司 | Switch control circuit, switch control method and switch power supply |
| CN114142739A (en) * | 2022-01-29 | 2022-03-04 | 深圳市芯茂微电子有限公司 | Control device for inverter and inverter |
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