CN214959288U

CN214959288U - Circuit for converting positive voltage into negative voltage

Info

Publication number: CN214959288U
Application number: CN202121181831.5U
Authority: CN
Inventors: 王恒; 陈科壬; 黄锦恒; 东莲正
Original assignee: Guangzhou DSPPA Audio Co Ltd
Current assignee: Guangzhou DSPPA Audio Co Ltd
Priority date: 2021-05-28
Filing date: 2021-05-28
Publication date: 2021-11-30
Anticipated expiration: 2031-05-28

Abstract

The utility model discloses a positive to negative voltage conversion circuit, which comprises a square wave generating circuit, a driving circuit and a voltage conversion circuit; the output end of the square wave generating circuit is connected with the input end of the driving circuit, the output end of the driving circuit is connected with the input end of the voltage conversion circuit, the output end of the voltage conversion circuit is connected with the negative power supply, and the input end of the voltage conversion circuit is connected with the positive power supply. The utility model discloses use a plurality of small-size components to realize that the positive voltage truns into the functional circuit of negative voltage, have that occupation space is little and need not consider the advantage of keeping apart the problem, can reduce power supply circuit's complexity, the utility model relates to a positive voltage changes circuit of negative voltage, but wide application in circuit design technical field.

Description

Circuit for converting positive voltage into negative voltage

Technical Field

The utility model belongs to the technical field of circuit design technique and specifically relates to a positive voltage changes circuit of negative voltage.

Background

With the development of society, audio power amplifiers (hereinafter, referred to as power amplifiers) are required more and more. The power amplifier comprises a digital power amplifier and an analog power amplifier, and the digital power amplifier has higher efficiency than the analog power amplifier. Digital power amplification must be a future trend based on energy efficiency considerations.

The existing digital power amplifier circuit structure generally comprises the following parts: 1. a signal buffer circuit; a PWM modulation circuit; 3. a drive circuit; 4. a power amplifier circuit.

For electronic devices that operate in a switching state, it is desirable to be able to perform the "on" and "off" operations of the electronic device in as short a time as possible in order to reduce the energy consumption of the switching device. The switching time of the digital power amplifier is greatly related to a driving circuit, the existing driving circuit generally uses a totem pole consisting of an NPN triode and a PNP triode, and the totem pole can use a single power supply or a double power supply for power supply. Due to the fact that the totem pole powered by the double power supplies is a negative power supply, the turn-off time is shorter than that of the totem pole powered by the single power supply, and energy loss is smaller. The power amplifier circuit of a digital power amplifier is generally a bridge circuit structure as shown in fig. 1 and fig. 2, and it can be known from the circuit principle that the source potentials of MOS transistors Q55, Q56, and Q61 (hereinafter, referred to as "upper arm") connected to a positive power supply are constantly changing. The source potential of the upper bridge arm is just the zero potential reference point of the upper bridge arm driving circuit, so the negative power supply of the existing driving circuit generally needs to be isolated, which undoubtedly can increase the complexity of the power circuit and the PCB area.

SUMMERY OF THE UTILITY MODEL

In view of this, embodiments of the present invention provide a positive to negative voltage circuit with small space occupation to reduce the complexity of the power circuit.

The embodiment of the utility model provides a positive voltage to negative voltage's circuit, including square wave generating circuit, drive circuit and voltage conversion circuit;

the output end of the square wave generating circuit is connected with the input end of the driving circuit, the output end of the driving circuit is connected with the input end of the voltage conversion circuit, the output end of the voltage conversion circuit is connected with the negative power supply, and the input end of the voltage conversion circuit is connected with the positive power supply.

Optionally, the square wave generating circuit includes an inverter, a first resistor, a second resistor, and a first capacitor;

wherein, a pin 1 of the phase inverter is connected with one end of the first resistor;

the 4 feet and the 5 feet of the phase inverter are connected with one end of the first capacitor, the other end of the first capacitor is connected with one end of the second resistor, and the other end of the second resistor is connected with the other end of the first resistor and the 6 feet of the phase inverter.

Optionally, the driving circuit includes a first triode, a first diode, a second diode, a third resistor, and a fourth resistor.

Optionally, the voltage conversion circuit includes a second transistor, a third transistor, a fourth diode, a fifth diode, a second capacitor, and a third capacitor.

Above-mentioned the utility model discloses technical scheme in the embodiment has following advantage: the circuit for converting positive voltage into negative voltage of the utility model comprises a square wave generating circuit, a driving circuit and a voltage converting circuit; the output end of the square wave generating circuit is connected with the input end of the driving circuit, the output end of the driving circuit is connected with the input end of the voltage conversion circuit, the output end of the voltage conversion circuit is connected with the negative power supply, and the input end of the voltage conversion circuit is connected with the positive power supply. The utility model discloses use a plurality of small-size components to realize that the positive voltage truns into the functional circuit of negative voltage, have that occupation space is little and need not consider the advantage of keeping apart the problem, can reduce power supply circuit's complexity.

Drawings

Fig. 1 is a circuit schematic diagram of a bridge connection mode of a conventional power amplifier circuit in the prior art;

FIG. 2 is a schematic diagram of a power amplifier circuit of a digital power amplifier in the prior art;

fig. 3 is a block diagram of the overall structure of a positive to negative voltage circuit according to the present invention;

fig. 4 is a schematic diagram of a positive to negative voltage circuit according to the present invention.

Detailed Description

To the complicated and shortcoming such as PCB area that occupy of above-mentioned current drive circuit negative power supply, the utility model provides an utilize a plurality of components to realize that positive voltage truns into the functional circuit of negative voltage, supply with totem-pole circuit and use. Specifically, the utility model provides a positive voltage to negative voltage conversion circuit, which comprises a square wave generating circuit, a driving circuit and a voltage conversion circuit;

Specifically, the following detailed description is made with reference to the accompanying drawings for implementing the present invention:

the switching frequency of the digital power amplifier is generally over 300kHz, and the on-time and the off-time of the MOS tube are only about 100 ns. Although the instantaneous charge/discharge current in the on time and the off time is large, the average current is not large because the time is short. The utility model discloses utilize switching power supply's thought, use a plurality of small-size components to realize that the positive voltage truns into the functional circuit of negative voltage into. As shown in fig. 3, the circuit mainly comprises the following parts: 1. a square wave generating circuit; 2. a drive circuit; 3. a voltage conversion circuit.

As shown in fig. 4, the square wave generating circuit is composed of an inverter U46, a first resistor R375, a second resistor R377, and a first capacitor C219;

the driving circuit consists of a first triode Q66, a first diode D106, a second diode D107, a third diode D108, a third resistor R373 and a fourth resistor R376;

the voltage conversion circuit is composed of a second triode Q65, a third triode Q67, a fourth diode D109, a fifth diode D110, a second capacitor C218 and a third capacitor C232.

The operation of the circuit shown in fig. 4 is as follows, after power-on, the + VCC sets the 1 st pin of U46 high through R373, D107, R374, R377, and R375, and the 6 th pin is set low through a second inversion to the 1 st pin, so as to form square wave oscillation to make the cathode of D107 repeatedly switch high and low, and the square wave generating circuit oscillates to generate square waves to the driving circuit.

The driving circuit drives the voltage conversion circuit to work, and the base of the Q66 of the driving circuit is switched to be high and low along with the repeated high and low switching of the cathode of the D107, so that the collector and the emitter of the Q66 are continuously switched on and off, and a driving signal with larger current is generated. When the driving signal is high, the CE pole of Q65 is turned on, the CE pole of Q67 of the voltage conversion circuit is turned off, and + VCC charges the C218 capacitor: + VCC → Q65 → C218 → D110 → GND _ VR, Ucap + VCC-0.7-0.7 after the capacitor C218 is charged, and the voltage direction is positive left and negative right. When the driving signal is low, the CE pole of Q65 is turned off, the CE pole of Q67 is turned on, and the left side of the capacitor C218 is grounded through Q67. Because the capacitor has the characteristic that the voltage cannot change suddenly, the polarity of the voltage of the capacitor is still positive left and negative right, and the right side of the capacitor is connected with the zero potential reference point GND _ VR, so that the voltage on the right side of the capacitor C218 becomes negative, and the capacitor C218 discharges: c218 → Q67 → GND _ VR → C232 → -VNN → D109, the amount of electricity discharged from C218 charges C232, and the polarity of the C232 voltage is positive at the lower side and positive at the upper side, and the lower side is a zero potential reference point, so the upper voltage is a negative value. Thereby achieving the change of the positive voltage + VCC to the negative voltage-VNN.

In this embodiment, the voltage level depends on the duty ratio of the high and low levels. Because the oscillation frequency of the oscillation circuit is high, the average current required by the external totem circuit is not large, and therefore the size of components used by the circuit is small.

When the driving signal is high, the CE pole of Q65 is turned on, the CE pole of Q67 of the voltage conversion circuit is turned off, and + VCC charges the C218 capacitor: + VCC → Q65 → C218 → D110 → GND _ VR, Ucap + VCC-0.7-0.7 after the capacitor C218 is charged, and the voltage direction is positive left and negative right. When the driving signal is low, the CE electrode of Q65 is turned off, the CE electrode of Q67 is turned on, and the left side of the capacitor C218 is grounded through Q67. Because the capacitor has the characteristic that the voltage cannot change suddenly, the polarity of the voltage of the capacitor is still positive left and negative right, and the right side of the capacitor is connected with the zero potential reference point GND _ VR, so that the voltage on the right side of the capacitor C218 becomes negative, and the capacitor C218 discharges: c218 → Q67 → GND _ VR → C232 → -VNN → D109, the amount of electricity discharged from C218 charges C232, and the polarity of the C232 voltage is positive at the lower side and positive at the upper side, and the lower side is a zero potential reference point, so the upper voltage is a negative value. Thereby achieving the change of the positive voltage + VCC to the negative voltage-VNN.

To sum up, compare with the totem pole negative supply circuit who uses on the current digital power amplifier, the utility model discloses it is little to have an occupation space, does not need to consider so easier realization of isolation problem, and the complexity is low.

The step numbers in the present embodiment are set for convenience of illustration only, the order between the steps is not limited at all, and the execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

While the preferred embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and such equivalent modifications or substitutions are intended to be included within the scope of the present invention as defined by the appended claims.

Claims

1. A positive to negative voltage circuit, comprising: the device comprises a square wave generating circuit, a driving circuit and a voltage conversion circuit;

2. The positive to negative voltage conversion circuit of claim 1, wherein: the square wave generating circuit comprises an inverter, a first resistor, a second resistor and a first capacitor;

3. The positive to negative voltage conversion circuit of claim 1, wherein: the driving circuit comprises a first triode, a first diode, a second diode, a third resistor and a fourth resistor.

4. The positive to negative voltage conversion circuit of claim 1, wherein: the voltage conversion circuit comprises a second triode, a third triode, a fourth diode, a fifth diode, a second capacitor and a third capacitor.