CN1909349A - Booster circuit with pulse width modulation limiter controller and its control method - Google Patents

Abstract

The invention discloses a structure of a booster circuit and a control method thereof. The circuit comprises: the DC/DC converter is used for receiving an input voltage, outputting an output voltage after boosting, and is provided with a pulse width modulation amplitude limiting controller and coupled with the converter, and is used for receiving an input voltage feedback signal, an output voltage feedback signal and an input current feedback signal of the converter and generating an output signal with a fixed period according to the input voltage feedback signal, the output voltage feedback signal and the input current feedback signal through the control of the controller. The output signal is used for controlling the on-off of a switch of the converter to generate the boosting.

Description

Booster circuit with pulse width modulation limiter controller and its control method

technical field

The invention relates to a voltage boosting circuit for controlling voltage boosting, in particular to a voltage boosting circuit with a pulse width modulation limiter controller.

Background technique

In the known technology related to the present invention, a schematic circuit diagram of a conventional boost circuit (boost circuit) 1 for controlling boost is shown in FIG. 1 . In FIG. 1, the boost circuit includes: a DC/DC boost converter (DC/DC boost converter) 11 and a feedback control circuit (feedback control circuit) 12, wherein the feedback control circuit 12 further includes a voltage/current A detector (voltage/current detector) 121 (for receiving an input voltage feedback signal S _Vi , an output voltage feedback signal S _Vo and an input current feedback signal S _Ii of the DC/DC boost converter 11 ), a modulator A modulator 123 , an oscillator 122 , a soft starting unit 124 and a feedback controller 125 . Wherein, an input voltage Vin becomes an output voltage Vo after being boosted, and the output voltage Vo is controlled by an output signal K of the feedback controller. The variation result of the output voltage Vo of the booster circuit 1 is gradually rising from an initial value S to a peak value P, and then slowly falling to a stable value Vo; the changing process is shown in FIG. 2 . The control principle of the voltage boosting circuit 1 is as follows: firstly, the voltage/current detector 121 converts the read signal into a voltage signal and outputs it to the modulator 123, after modulating the pulse cycle with the signal from the oscillator 122, After being sent to the feedback controller 125 for comparison with the signals generated by the oscillator 122 and the soft-start controller 124, a control signal K is output to control the opening and closing of a switch Q1 of the boost circuit 1 to generate the boost voltage .

The rising waveform of the above-mentioned output voltage Vo is shown in Figure 2, from the initial value S to the peak value P and then drops to the stable voltage value Vo. Because a traditional boost circuit 1 in this known technology will make the highest value of the output voltage Vo rise to the P value of a peak voltage, so in the selection of components of the traditional boost circuit 1, for example: the switch Q1, a The diode D, and an output capacitor C1, etc., must use components with a higher voltage level or higher reliability in consideration of their withstand voltage, thus resulting in relatively high relative manufacturing costs; and If the conventional boost circuit 1 is used, because the output voltage Vo will rise to a P value greater than the peak voltage of the predetermined output voltage value Vo, it is relatively less expensive in terms of the additional power consumption and other factors. economy.

Therefore, in view of the shortcomings of the known technology, the inventor proposes the "boost circuit with pulse width modulation limiter controller and its control method" of the present invention.

Contents of the invention

The main purpose of the present invention is to provide a booster circuit with a pulse width modulation limiter controller and its control method, which can prevent the output voltage Vo of the booster circuit from rising to a P value exceeding the peak voltage of the predetermined output voltage value Vo. Value, in order to save unnecessary power loss and achieve the use of components of the boost circuit with relatively low withstand voltage conditions to reduce its total cost (including manufacturing, storage and transportation costs, etc.).

Another main object of the present invention is to provide a boost circuit with a pulse width modulation limiter controller, the circuit includes: a DC/DC converter (DC/DC converter), used to receive an input voltage, and Outputting an output voltage after boosting, and a feedback control circuit (feedback control circuit), with a pulse-width modulation limiting controller (pulse-width modulation limiting controller), and coupled to the converter, for receiving the converter An input voltage feedback signal, an output voltage feedback signal and an input current feedback signal and a control by the controller thereby generate an output signal with a fixed period, wherein the output signal is used to control a switch of the converter The opening and closing of , generate the boost.

According to the above idea, the output signal is a pulse, and when the output voltage rises from an initial value to a stable value, the pulse has a first amplitude, and when the output voltage rises to the stable value, the pulse is With a second amplitude.

According to the above idea, the second amplitude is larger than the first amplitude.

According to the above idea, the control circuit further includes: a voltage/current detector (voltage/current detector), coupled to the converter and the controller, for receiving the input voltage feedback signal, the output voltage feedback signal and the input The current feedback signal and generate a voltage output signal accordingly, an oscillator (oscillator), used to generate a sawtooth wave, a modulator (modulator), coupled to the voltage/current detector, the controller and the oscillator, Used to generate a modulation signal, a soft start controller (soft starting unit), coupled to the pulse width modulation limiter controller, used to generate a soft start control signal, and a feedback controller (feedback controller), coupled to the The oscillator, the modulator and the soft-start controller are used to generate the output signal.

According to the above idea, the PWM limiting controller outputs a first, a second and a third control signal to the voltage/current detector, the modulator and the soft-start controller respectively, thereby controlling the At least one of the voltage/current detector, the modulator and the soft-start controller generates the output signal.

According to the idea above, the first control signal is a first voltage clamping signal, which is used to make the voltage/current detector output a first voltage with a first fixed value, and the second control signal is a one-cycle clipping signal. signal, used to make the modulation signal output by the modulator have a fixed period, and the third control signal is a second voltage clamping signal, used to make the soft-start controller output a first voltage with a second fixed value Second voltage.

According to the above idea, the PWM limiting controller further includes: a circuit starter for starting the PWM limiting controller and outputting a starting signal, a first voltage clamper coupled to the circuit The starter and the voltage/current detector are used to receive the startup signal and output the first control signal, and a limiter is coupled to the first voltage clamper and the modulator to receive the startup signal and output the first control signal. Outputting the second control signal, and a second voltage clamp coupled to the period limiter and the soft-start controller for receiving the start signal and outputting the third control signal.

According to the above idea, the modulator is a pulse-width modulator.

According to the above idea, the feedback controller is a NAND gate.

According to the above idea, the converter is one of a DC/DC boost converter and a DC/DC buck-boost converter.

According to the above idea, the switch is a metal oxide semiconductor field effect transistor (MOSFET), and an output terminal of the feedback control circuit is coupled to a gate of the transistor.

The second main purpose of the present invention is to provide a control method of a boost circuit with a pulse width modulation limiter controller, wherein the boost circuit includes: a DC/DC converter (DC/DC converter) for receiving an input The voltage is boosted to output an output voltage and a feedback control circuit (feedback control circuit), with a pulse-width modulation limiting controller (pulse-widthmodulation limiting controller), a voltage/current detector (voltage/current detector ), an oscillator (oscillator), a modulator (modulator), a soft start controller (soft starting unit) and a feedback controller (feedback controller), and coupled to the converter, the method includes the following steps: ( a) transmitting an input voltage feedback signal, an output voltage feedback signal and an input current feedback signal generated by the converter to the voltage/current detector; (b) respectively transmitting a first generated by the controller , a second and a third control signal to the voltage/current detector, the modulator and the soft-start controller, thereby controlling at least one of the voltage/current detector, the modulator and the soft-start controller One; (c) sending a voltage output signal generated by the voltage/current detector to the modulator; (d) sending a sawtooth wave generated by the oscillator to the modulator and the feedback controller; ( e) transmit a modulation signal generated by the modulator to the feedback controller; (f) transmit a soft-start control signal generated by the soft-start controller to the feedback controller; (g) transmit a soft-start control signal generated by the feedback controller; An output signal with a fixed period generated by the controller is sent to the converter; and (h) a switch of the converter is controlled by the output signal to turn on and off, so that the output voltage rises from an initial value to a stable value to reach the boost.

According to the idea above, the first control signal is a first voltage clamping signal, which is used to make the voltage/current detector output a first voltage with a first fixed value, and the second control signal is a one-cycle clipping signal. signal, used to make the modulation signal output by the modulator have a fixed period, and the third control signal is a second voltage clamping signal, used to make the soft-start controller output a voltage with a second fixed value second voltage.

According to the above idea, the PWM limiting controller further includes: a circuit starter for starting the PWM limiting controller and outputting a starting signal, a first voltage clamper coupled to the circuit The starter and the voltage/current detector are used to receive the startup signal and output the first control signal, and a limiter is coupled to the first voltage clamper and the modulator to receive the startup signal and output the first control signal. Outputting the second control signal, and a second voltage clamp coupled to the period limiter and the soft-start controller for receiving the start signal and outputting the third control signal.

According to the above idea, the output signal is a pulse, and when the output voltage rises from an initial value to a stable value, the pulse has a first amplitude, and when the output voltage rises to the stable value, the pulse is With a second amplitude.

According to the above idea, the second amplitude is larger than the first amplitude.

Description of drawings

FIG. 1 is a schematic circuit diagram showing a conventional boost circuit in the prior art;

FIG. 2 is a waveform diagram showing that the output voltage of the traditional boost circuit as shown in FIG. 1 rises from an initial value S to a peak value P and then drops to a stable value Vo and the corresponding output signal K of the feedback controller;

Figure 3 (a) and (b) show the first and second preferred embodiments of the present invention with a PWM limiter controller and DC/DC boost converter and with a PWM limiter controller and a schematic circuit diagram of a boost circuit of a DC/DC buck-boost converter;

Fig. 4 is a waveform diagram showing that the output voltage of the first preferred embodiment as shown in Fig. 3 (a) rises from an initial value S to a stable value Vo and the output signal K of the feedback controller corresponding thereto; and

FIG. 5 is a circuit block diagram showing the PWM limiter controller of the present invention.

Wherein, the reference signs are explained as follows:

1: Traditional boost circuit 11: DC/DC boost converter

12: Feedback control circuit 121: Voltage/current detector 122: Oscillator

123: Modulator 124: Soft-start controller 125: Feedback controller

2: Boost circuit of the first preferred embodiment of the present invention 21: DC/DC boost converter

22: Feedback control circuit 221: Voltage/current detector

222: PWM limiter controller 2221: Circuit starter

2222: First voltage clamper 2223: Period limiter

2224: second voltage clamper 223: oscillator 224: modulator

225: Soft start controller 226: Feedback controller

3: The boost circuit of the second preferred embodiment of the present invention

31: DC/DC buck-boost converter 32: Feedback control circuit

321: Voltage/Current Detector 322: Pulse Width Modulation Limiting Controller 323: Oscillator

324: Modulator 325: Soft-start controller 326: Feedback controller

Detailed ways

As shown in FIG. 3( a ), it is a schematic circuit diagram of a booster circuit 2 with a PWM limiter controller according to the first preferred embodiment of the present invention. The boost circuit 2 includes: a DC/DC boost converter (DC/DC boost converter) 21 for receiving an input voltage Vin, and outputting an output voltage Vo after boosting, and a feedback control circuit 22 . Wherein, the feedback control circuit 22 further includes: a voltage/current detector (voltage/current detector) 221, a pulse-width modulation limiting controller (pulse-widthmodulation limiting controller) 222, an oscillator (oscillator) 223, an A modulator (modulator) 224, a soft start controller (soft starting unit) 225 and a feedback controller (feedback controller) 226, the feedback control circuit 22 is coupled to the DC/DC boost converter 21 for receiving the An input voltage feedback signal S _Vi , an output voltage feedback signal S _Vo and an input current feedback signal S _Ii of the DC/DC boost converter 21 are controlled by the PWM limiter controller 222 , according to which An output signal K with a fixed period T (as shown in FIG. 4 ) is generated. Wherein, the PWM limiting controller 222 respectively outputs a first control signal SC1, a second control signal SC2 and a third control signal SC3 to the voltage/current detector 221, the modulator 224 and the soft start The controller 225 controls at least one of the voltage/current detector 221 , the modulator 224 and the soft-start controller 225 accordingly to generate the output signal K. The output signal K is used to control a switch Q1 (which can be a MOSFET) of the converter 21 to turn on and off to generate the boost voltage. In addition, the voltage/current detector 221 is coupled to the DC/DC boost converter 21 and the PWM limiting controller 222 for receiving the input voltage feedback signal S _Vi , the output voltage feedback signal S _Vo and The input current feedback signal S _Ii generates a voltage output signal accordingly, and the oscillator 223 is used to generate a sawtooth wave. The modulator 224 is coupled to the voltage/current detector 221 , the PWM limiter controller 222 and the oscillator 223 for generating a modulation signal SM. The soft-start controller 225 is coupled to the PWM limiter controller 222 for generating a soft-start control signal (which is a pulse). The feedback controller 226 is coupled to the oscillator 223 , the modulator 224 and the soft-start controller 225 for generating the output signal K. In addition, the feedback controller 226 is a NAND gate, the modulator is a pulse-width modulator, and the output signal K is a pulse. When the output voltage Vo rises from an initial value S to a stable value Vo, the pulse has a first amplitude W1, and after the output voltage rises to the stable value, the booster circuit 2 enters a normal operation, At this time, the pulse has a second amplitude W2, and due to a load of the booster circuit 2, the second amplitude W2 will be greater than the first amplitude W1. The PWM limiter controller 222 respectively outputs a first control signal SC1, a second control signal SC2 and a third control signal SC3 to the voltage/current detector 221, the modulator 224 and the soft-start controller 225 , according to which at least one of the voltage/current detector 221 , the modulator 224 and the soft-start controller 225 is controlled to generate the output signal K. The above-mentioned first control signal SC1 is a first voltage clamping signal, which is used to make the voltage/current detector 221 output a first voltage with a first fixed value, and the second control signal SC2 is a one-cycle clipping signal. signal, used to make the modulation signal SM output by the modulator 224 have a fixed period, and the third control signal SC3 is a second voltage clamping signal, used to make the soft-start controller 225 output a second A second voltage of a fixed value.

As shown in FIG. 3( b ), it is a schematic circuit diagram of a booster circuit 3 with a PWM limiter controller according to a second preferred embodiment of the present invention. The boost circuit 3 includes: a DC/DC buck-boost converter (DC/DC buck-boost converter) 31 for receiving an input voltage Vin, and outputting an output voltage Vo after a boost, and a feedback control Circuit 32, wherein the feedback control circuit 32 further includes a voltage/current detector (voltage/current detector) 321, a pulse-width modulation limiting controller (pulse-width modulation limiting controller) 322, a modulator (modulator) 324 , an oscillator (oscillator) 323, a soft start controller (soft starting unit) 325 and a feedback controller (feedback controller) 326, and coupled to the DC/DC buck-boost converter 31, in order to receive the DC An input voltage feedback signal SVi, an output voltage feedback signal SVo and an input current feedback signal SIi of the DC/DC buck-boost converter 31 and a control by the PWM limiter controller 321 generate a constant The output signal K of period T (as shown in FIG. 4 ). Wherein, the output signal K is used to control the opening and closing of a switch Q1 of the converter 31 to generate the boost voltage. The difference between the voltage boosting circuit 3 of the second preferred embodiment of the present invention and the voltage boosting circuit 2 of the first preferred embodiment of the present invention with the PWM limiting controller is only that The boost circuit 3 of the second preferred embodiment includes a DC/DC boost converter 31, and the boost circuit 2 of the first preferred embodiment of the present invention includes a DC/DC boost converter 21, both All can achieve the function of outputting an output voltage Vo after an input voltage Vin is boosted; the rest of the circuit and operating principle are exactly the same.

The boost circuit 2 of the above-mentioned first preferred embodiment of the present invention and the boost circuit 3 of the second preferred embodiment of the present invention (as shown in Figure 3 (a) and (b)) all include an identical pulse width Modulation clipping controller (see 222 of Fig. 3(a) and 322 of Fig. 3(b)). Now take the PWM limiter controller 222 included in the booster circuit 2 of the first preferred embodiment of the present invention as an example to describe the following. A circuit block diagram of a preferred embodiment of the PWM limiting controller is shown in FIG. 5 . Wherein, the PWM limiting controller 222 further includes: a circuit starter (circuit starter) 2221 for starting the PWM limiting controller 222 and outputting a starting signal Str, a first voltage clamper (first voltage clamper) 2222, coupled to the circuit starter 2221 and the voltage/current detector 221, for receiving the start signal Str and outputting the first control signal SC1, a cycle limiter (time period limiter) 2223, coupled to The first voltage clamper 2222 and the modulator 224 are used to receive the start signal Str and output the second control signal SC2; and a second voltage clamper (second voltage clamper) 2224, coupled to the period limiter The device 2223 and the soft-start controller 225 are used to receive the start signal Str and output the third control signal SC3.

Regarding the operating principle shared by the voltage boosting circuit 2 of the first preferred embodiment of the present invention and the voltage boosting circuit 3 of the second preferred embodiment of the present invention (please refer to Fig. 3 (a) and (b)), it can be The boost circuit 2 of the first preferred embodiment of the present invention is taken as an example, and its control method is described as follows. The method includes the following steps: (a) transmitting an input voltage feedback signal SVi, an output voltage feedback signal SVo and an input current feedback signal SIi generated by the converter 21 to the voltage/current detector 221; (b) Sending a first control signal SC1, a second control signal SC2 and a third control signal SC3 generated by the controller 222 to the voltage/current detector 221, the modulator 224 and the soft-start controller 225 respectively , thereby controlling at least one of the voltage/current detector 221, the modulator 224 and the soft-start controller 225; (c) transmitting a voltage output signal generated by the voltage/current detector 221 to the modulator (d) send a sawtooth wave generated by the oscillator 223 to the modulator 224 and the feedback controller 226; (e) send a modulation signal SM generated by the modulator 224 to the feedback controller (f) transmit a soft start control signal generated by the soft start controller 225 to the feedback controller 226; (g) transmit a fixed period T (such as 4) output signal K to the converter 21; and (h) the output signal K controls the opening and closing of a switch Q1 of the converter 21, so that the output voltage Vo rises from an initial value S to A stable value Vo is achieved for the boost.

It can be seen from the above description that the present invention provides a boost circuit with a pulse width modulation limiter controller and its control method, which can prevent the output voltage Vo of the boost circuit from rising to a peak value exceeding the predetermined output voltage value Vo The P value of the voltage is used to save unnecessary power loss and achieve the advantages of using components of the boost circuit with relatively low withstand voltage conditions to relatively reduce its total cost (including manufacturing, storage and transportation costs, etc.).

Therefore, although the present invention has been described in detail by the above embodiments, those skilled in the art can make various modifications without departing from the protection scope of the claims.

Claims (10)

1. A step-up circuit comprising: a DC/DC converter for receiving an input voltage and outputting an output voltage after a step-up; and A feedback control circuit, having a pulse width modulation limiter controller, coupled to the converter, used to receive an input voltage feedback signal, an output voltage feedback signal and an input current feedback signal of the converter and pass the control A control of the device generates an output signal with a fixed period accordingly, Wherein the output signal is used to control a switch of the converter to turn on and off to generate the boost voltage. 2. The circuit according to claim 1, wherein the output signal is a pulse, and when the output voltage rises from an initial value to a stable value, the pulse has a first amplitude, and when the output voltage After rising to the stable value, the pulse has a second amplitude. 3. The circuit according to claim 1, wherein the control circuit further comprises: a voltage/current detector, coupled to the converter and the controller, for receiving the input voltage feedback signal, the output voltage feedback signal and the input current feedback signal and generating a voltage output signal accordingly; an oscillator for generating a sawtooth wave; a modulator, coupled to the voltage/current detector, the controller and the oscillator, for generating a modulation signal; a soft start controller, coupled to the pulse width modulation limiter controller, for generating a soft start control signal; and A feedback controller, coupled to the oscillator, the modulator and the soft-start controller, is used to generate the output signal. 4. The circuit of claim 3, wherein: The PWM limiting controller outputs a first, a second and a third control signal to the voltage/current detector, the modulator and the soft-start controller respectively, thereby controlling the voltage/current detector . At least one of the modulator and the soft-start controller generates the output signal; The first control signal is a first voltage clamping signal, used to make the voltage/current detector output a first voltage with a first fixed value, and the second control signal is a cycle limiting signal, used to make The modulating signal output by the modulator has a fixed period, and the third control signal is a second voltage clamping signal, which is used to make the soft-start controller output a second voltage with a second fixed value; and/ or The PWM limiter controller further includes: A circuit starter, used to start the pulse width modulation limiter controller and output a start signal; a first voltage clamper, coupled to the circuit starter and the voltage/current detector, for receiving the startup signal and outputting the first control signal; a limiter, coupled to the first voltage clamp and the modulator, for receiving the activation signal and outputting the second control signal; and A second voltage clamper, coupled to the period limiter and the soft-start controller, is used for receiving the start signal and outputting the third control signal. 5. The circuit of claim 3, wherein: the modulator is a pulse width modulator; and/or The feedback controller is a NAND gate. 6. The circuit of claim 1, wherein: The converter is one of a DC/DC boost converter and a DC/DC buck-boost converter; and/or The switch is a MOSFET, and an output end of the feedback control circuit is coupled to a gate of the transistor. 7. A control method for a boost circuit, wherein the boost circuit includes: a DC/DC converter for receiving an input voltage and outputting an output voltage after a boost and a feedback control circuit with a pulse A wide modulation and clipping controller, a voltage/current detector, an oscillator, a modulator, a soft-start controller and a feedback controller, coupled to the converter, the method includes the following steps: (a) transmitting an input voltage feedback signal, an output voltage feedback signal and an input current feedback signal generated by the converter to the voltage/current detector; (b) sending a first, a second and a third control signal generated by the controller to the voltage/current detector, the modulator and the soft-start controller respectively, thereby controlling the voltage/current at least one of a detector, the modulator, and the soft-start controller; (c) transmitting a voltage output signal generated by the voltage/current detector to the modulator; (d) sending a sawtooth wave generated by the oscillator to the modulator and the feedback controller; (e) transmitting a modulated signal generated by the modulator to the feedback controller; (f) transmitting a soft start control signal generated by the soft start controller to the feedback controller; (g) transmitting an output signal with a fixed period generated by the feedback controller to the converter; and (h) controlling a switch of the converter to be turned on and off by the output signal, so that the output voltage rises from an initial value to a stable value to achieve the boosted voltage. 8. The method according to claim 7, wherein the first control signal is a first voltage clamping signal for causing the voltage/current detector to output a first voltage with a first fixed value , the second control signal is a one-cycle clipping signal to make the modulation signal output by the modulator have a fixed period, and the third control signal is a second voltage clamping signal to make the soft-start control The converter outputs a second voltage with a second fixed value. 9. The method according to claim 7, wherein the PWM limiting controller further comprises: A circuit starter, used to start the pulse width modulation limiter controller and output a start signal; a first voltage clamper, coupled to the circuit starter and the voltage/current detector, for receiving the startup signal and outputting the first control signal; a limiter, coupled to the first voltage clamp and the modulator, for receiving the activation signal and outputting the second control signal; and A second voltage clamper, coupled to the period limiter and the soft-start controller, is used for receiving the start signal and outputting the third control signal. 10. The method of claim 7, wherein: The output signal is a pulse, and when the output voltage rises from an initial value to a stable value, the pulse has a first amplitude, and when the output voltage rises to the stable value, the pulse has a second amplitude ;and The second amplitude is larger than the first amplitude.

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