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pwm control circuit and switching power supply device

A technology for controlling circuits and circuits, applied to output power conversion devices, electrical components, and conversion of AC power input to DC power output, etc., which can solve problems such as inability to cope with variable duty ratios, etc.

Active Publication Date: 2018-06-12
MURATA MFG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, such a phase difference cannot be set in a conventional general PWM control circuit that generates a PWM signal by comparing a triangular wave signal and a modulation signal.
[0013] In addition, when it is desired to change the duty ratio of the quasi-rectangular wave by an external signal, etc., the same cannot be done.
[0014] In addition, although a plurality of the above-mentioned controllers are used when it is desired to synchronize the phases of a plurality of independently controlled quasi-rectangular wave outputs, since each has a triangular wave oscillator, it cannot cope with

Method used

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  • pwm control circuit and switching power supply device
  • pwm control circuit and switching power supply device
  • pwm control circuit and switching power supply device

Examples

Experimental program
Comparison scheme
Effect test

no. 1 Embodiment approach 》

[0052] figure 1 It is a block diagram of the PWM control circuit 101 according to the first embodiment of the present invention. The PWM control circuit 101 includes a square wave signal input terminal 11 for inputting a square wave signal, a modulation signal input terminal 12 , a first modulated signal output terminal 21 , and a second modulated signal output terminal 22 .

[0053] In addition, this PWM control circuit 101 includes a first ramp wave generation circuit 31 , a second ramp wave generation circuit 32 , a first comparison circuit 41 , and a second comparison circuit 42 . The second ramp wave generating circuit 32 is composed of the ramp wave generating circuit 30 and the inverting circuit 29 .

[0054] The first ramp wave generation circuit 31 generates a first ramp wave in synchronization with the rise of the square wave signal input to the square wave signal input terminal 11 . The ramp wave referred to here is a waveform that repeatedly starts sweeping the ...

no. 2 Embodiment approach 》

[0070] Figure 4 It is a circuit diagram of the PWM control circuit 102 of 2nd Embodiment. This PWM control circuit 102 includes a first ramp wave generation circuit 31 , a second ramp wave generation circuit 32 , a first comparison circuit 41 , and a second comparison circuit 42 . and in the first embodiment figure 2 The PWM control circuit 101 shown is different in that resistors R11, R21 are provided instead of the constant current circuits CC1, CC2. That is, in this PWM control circuit 102, the first time constant circuit 51 is constituted by the resistor R11 and the first capacitor C11. Similarly, the second time constant circuit 52 is constituted by the resistor R21 and the second capacitor C21.

[0071] Figure 5 It is a diagram showing a charging current path when the first switching element SW11 is turned on and a discharging current path when the first switching element SW11 is turned off. When the first switching element SW11 is turned on, a charging current f...

no. 3 Embodiment approach 》

[0080] Figure 7 It is a circuit diagram of the PWM control circuit 103 of 3rd Embodiment. The PWM control circuit 103 operates with the power supply Vdc1 as the power supply voltage. The first ramp wave generating circuit 31 is composed of a constant current circuit CC1 , a first capacitor C11 , a diode D11 , a resistor R12 , a first switching element SW11 , and an inverting circuit 29 . The second ramp wave generating circuit 32 is composed of a constant current circuit CC2, a second capacitor C21, a diode D21, a resistor R22, and a second switching element SW21. Both the first comparison circuit 41 and the second comparison circuit 42 are composed of comparators.

[0081] exist Figure 7 Among them, the first time constant circuit 51 is constituted by the constant current circuit CC1 and the first capacitor C11. Similarly, the second time constant circuit 52 is constituted by the constant current circuit CC2 and the second capacitor C21. As described later, in Figure...

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Abstract

Provided is a PWM control circuit in which a square wave signal having a discretionary frequency and duty ratio is input from a terminal (11), a modulation signal is input from a terminal (12), and two modified signals having different timing (phase) are output from terminals (21, 22). A first ramp wave generation circuit (31) generates a first ramp wave that is synchronized with the rising edge of the square wave signal. A second ramp wave generation circuit (32) generates a second ramp wave that is synchronized with the falling edge of the square wave signal. A first comparison circuit (32) generates a first modulated signal by inverting the level in accordance with the result of comparing the first ramp wave and the modulation signal. A second comparison circuit (42) generates a second modulated signal by inverting the level in accordance with the result of comparing the second ramp wave and the modulation signal. As a result, two PWM signals having a phase difference other than 180° are generated, and a quasi-square wave signal having a duty ratio other than 50% is obtained.

Description

technical field [0001] The present invention relates to a PWM control circuit for generating two PWM signals having a phase difference, and a switching power supply device including the same in a switching control unit. Background technique [0002] An example of a switching control circuit based on PWM control in a switching power supply device is shown in Patent Document 1. In addition, Patent Document 2 discloses a power supply device that applies a quasi-rectangular wave AC voltage to a capacitive load. [0003] In general, a PWM control circuit basically includes: a triangular wave generating circuit that generates a triangular wave (sawtooth wave); and a comparator circuit that compares the triangular wave signal with a modulated signal. In the switching control circuit of the switching power supply device, the modulation signal is an output voltage detection signal, and the switching element is driven by the output signal of the PWM control circuit. [0004] Figure...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/538
CPCH02M7/53803
Inventor 井尻康则三桥宗太郎
Owner MURATA MFG CO LTD