Power supply circuit with voltage converting circuits and control method therefor
An exemplary power supply circuit ( 20 ) includes an input terminal ( 201 ), an output terminal ( 202 ), voltage converting circuits ( 23, 24 ), and a pulse width modulation circuit ( 22 ). The input terminal is capable of receiving a direct current voltage. The output terminal is capable of providing voltage to a load circuit. The voltage converting circuits are connected in parallel between the input terminal and the output terminal. The pulse width modulation circuit is configured to control the voltage converting circuits to convert the direct current voltage into pulse voltages. A phase of each pulse voltage is delayed relative to that of an adjacent preceding pulse voltage.
1 . A power supply circuit, comprising:
an input terminal capable of receiving a direct current voltage;
an output terminal capable of providing voltage to a load circuit;
a plurality of voltage converting circuits connected in parallel between the input terminal and the output terminal; and
a pulse width modulation circuit;
wherein the pulse width modulation circuit is configured to control the plurality of voltage converting circuits to convert the direct current voltage into a plurality of pulse voltages, wherein a phase of each pulse voltage is delayed relative to that of an adjacent preceding pulse voltage.
2 . The power supply circuit of claim 1 , further comprising a rectifying circuit capable of receiving an alternating current voltage, and outputting a direct current voltage to the plurality of voltage converting circuits.
3 . The power supply circuit of claim 1 , further comprising a filter capacitor connected between the output terminal and ground.
4 . The power supply circuit of claim 3 , wherein each voltage converting circuit comprises a transformer with a primary winding and a secondary winding, a transistor, and a rectifying diode, one end of the primary winding is connected to the input terminal, the other end of the primary winding is connected to a drain electrode of the transistor, a source electrode of the transistor is grounded, one end of the secondary winding is grounded, and the other end of the secondary winding is connected to the output terminal via the rectifying diode.
5 . The power supply circuit of claim 4 , wherein each voltage converting circuit further comprises a resistor, and the source electrode of the transistor is grounded via the resistor.
6 . The power supply circuit of claim 1 , further comprising a feedback circuit configured for feeding a signal corresponding to an output voltage of the output terminal back to the pulse width modulation circuit.
7 . The power supply circuit of claim 1 , wherein the plurality of voltage converting circuits is two voltage converting circuits, and the phase delay between the two pulse voltages is 120 degrees.
8 . A power supply circuit, comprising:
an input terminal capable of receiving external voltage;
an output terminal capable of providing voltage to a load;
N voltage converting circuits connected in parallel between the input terminal and the output terminal, wherein N is a natural number larger than one; and
a pulse width modulation circuit;
wherein the pulse width modulation circuit is configured to provide N voltage control signals to the voltage converting circuits, respectively, with a phase delay existing between each two adjacent voltage control signals, and the voltage converting circuits are configured to generate N pulse voltages according to the N voltage control signals.
9 . The power supply circuit of claim 8 , further comprising a rectifying circuit configured for receiving alternating current voltage, and outputting direct current voltage to the voltage converting circuits.
10 . The power supply circuit of claim 8 , further comprising a filter capacitor connected between the output terminal and ground.
11 . The power supply circuit of claim 10 , wherein each voltage converting circuit comprises a transformer with a primary winding and a secondary winding, a transistor, and a rectifying diode, one end of the primary winding is connected to the input terminal, the other end of the primary winding is connected to a drain electrode of the transistor, a source electrode of the transistor is grounded, one end of the secondary winding is grounded, and the other end of the secondary winding is connected to the output terminal via the rectifying diode.
12 . The power supply circuit of claim 11 , wherein each voltage converting circuit further comprises a resistor, and the source electrode of the transistor is grounded via the resistor.
13 . The power supply circuit of claim 8 , further comprising a feedback circuit configured for feeding a signal corresponding to an output voltage of the output terminal back to the pulse width modulation circuit.
14 . The power supply circuit of claim 9 , wherein the voltage converting circuits are configured to generate the pulse voltages with a phase delay existing between each two adjacent pulse voltages, the phase delay between each two adjacent pulse voltages corresponding to the phase delay between each two adjacent voltage control signals.
15 . The power supply circuit of claim 14 , wherein the phase delay between each two adjacent pulse voltages is 360/(N+1) degrees.
16 . A control method for a power supply circuit, the method comprising:
generating N voltage control signals, N being a natural number larger than one, a phase delay existing between each two adjacent voltage control signals;
generating N pulse voltages by N voltage converting circuits according to the voltage control signals, a phase delay existing between each two adjacent pulse voltages; and
providing the pulse voltages to a load.
17 . The control method of claim 16 , wherein the phase delay between each two adjacent voltage control signals is 360/(N+1) degrees.
18 . The control method of claim 16 , wherein the phase delay between each two adjacent pulse voltages is 360/(N+1) degrees.