Switching power supply device and switching power supply system

• US 7,091,711 B2
• Filed: 12/16/2005
• Issued: 08/15/2006
• Est. Priority Date: 06/07/2002
• Status: Expired due to Fees

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Technology Corporation (Renesas Electronics Corporation)
• Inventors: Yoshida, Shinichi, Sase, Takashi, Tazawa, Tomohiro, Tateno, Kouji
• Primary Examiner(s): BERHANE, ADOLF D
• Application Number:
  US11/304,903
• Publication Number:
  US 20060091870A1
• Time in Patent Office: 242 Days
• Field of Search: 323/282, 323/283, 323/284, 323/285, 323/351
• US Class Current: 323/282
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 3/1563 without using an external clock H02M3/158 takes precedence
• CPC Class Codes: H02M 3/1588 comprising at least one synchronous rectifier element H02M3/1582, H02M3/1584 take precedence
• CPC Class Codes: H02M 3/3385 with automatic control of output voltage or current H02M3/33561 takes precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

There is provided a switching power supply device of hysteresis current mode control system which assures excellent response characteristic for change of output current and reduction of power consumption. In a switching regulator of hysteresis current mode control system, a sense resistor connected in series to a coil is eliminated, a serially connected resistor and a capacitor are connected in parallel to a coil in place of such sense resistor. Thereby, a potential of a connection node of these resistor and capacitor is inputted to a comparator circuit having the hysteresis characteristic for comparison with the reference voltage. Accordingly, a switch may be controlled for ON and OFF states.

Claims

1. A switching power supply device comprising:

a first power supply terminal;

a second power supply terminal;

a switching element having a control terminal, a source terminal and a drain terminal, one of the source and drain terminals being coupled to the first power supply terminal;

an inductor having a first terminal coupled to the other of the source and drain terminals of the switching element and a second terminal;

a first capacitor having a first terminal coupled to the second terminal of the inductor and to be coupled to a load element and a second terminal coupled to the second power supply terminal;

a first resistor having a first terminal coupled to the other of the source and drain terminals of the switching element and a second terminal;

a second capacitor having a first terminal coupled to the second terminal of the first resistor and a second terminal coupled to the second terminal of the inductor; and

a hysteresis comparator having an input terminal coupled to the second terminal of the first resistor and an output terminal coupled to the control terminal of the switching element, the hysteresis comparator comparing a voltage received from the input terminal thereof with a first and a second threshold voltage relating to a hysteresis characteristic thereof and providing a discrimination result to the control terminal of the switching element.

2. The switching power supply device according to claim 1, wherein the hysteresis comparator outputs the discrimination result for the control terminal so as to control the voltage between the first threshold voltage and the second threshold voltage.

3. A power supply device, comprising:

a power supply terminal;

a ground terminal;

a P-channel MOSFET which has a control terminal, a source terminal coupled to the power supply terminal, and a drain terminal;

an N-channel MOSFET which has a control terminal, a source terminal coupled to the ground terminal, and a drain terminal coupled to the drain terminal of the P-channel MOSFET;

an inductor having a first terminal coupled to the drain terminal of the P-channel MOSFET and a second terminal;

a first capacitor having a first terminal coupled to the second terminal of the inductor and to be coupled to a load element and a second terminal coupled to the ground terminal;

a first resistor having a first terminal coupled to the drain terminal of the P-channel MOSFET and a second terminal;

a second capacitor having a first terminal coupled to the second terminal of the first resistor and a second terminal coupled to the second terminal of the inductor;

a second resistor having a first terminal coupled to a second terminal of the first resistor and a second terminal;

a hysteresis comparator having a first input terminal coupled to the second terminal of the first resistor and an output terminal, the hysteresis comparator comparing a first voltage received from the first input terminal thereof with a first and a second threshold voltage; and

a switching control circuit which receives a discrimination result from the output terminal of the hysteresis comparator and controls the control terminals of the P-channel and the N-channel MOSFET based on the discrimination result.

4. The power supply device according to claim 3, further comprising:

a third resistor having a first terminal coupled to the first terminal of the first capacitor and a second terminal;

a fourth resistor having a first terminal coupled to the second terminal of the third resistor and a second terminal coupled to the ground terminal; and

an error amp having a first input terminal which receives a second voltage from the second terminal of the third resistor, a second input terminal which receives a first reference voltage and an output terminal outputting an output signal to a second input terminal of the hysteresis comparator,

wherein the second terminal of the second resistor is coupled to the ground terminal.

5. The power supply device according to claim 3, wherein a predetermined voltage is input to a second input terminal of the hysteresis comparator.

6. The power supply device according to claim 5, wherein the second terminal of the second resistor is coupled to the ground terminal.

7. The power supply device according to claim 3, wherein the hysteresis comparator outputs the discrimination result so as to control the first voltage between the first threshold voltage and the second threshold voltage.

8. A power supply device, comprising:

a power supply terminal;

a ground terminal;

a first N-channel MOSFET which has a control terminal, a source terminal, and a drain terminal which is coupled to the power supply terminal;

a second N-channel MOSFET which has a control terminal, a source terminal coupled to the ground terminal, and a drain terminal which is coupled to the source terminal of the first N-channel MOSFET;

an inductor having a first terminal coupled to the source terminal of the first N-channel MOSFET and a second terminal;

a first capacitor having a first terminal coupled to the second terminal of the inductor and to be coupled to a load element and a second terminal coupled to the ground terminal;

a first resistor having a first terminal coupled to the source terminal of the first N-channel MOSFET and a second terminal;

a second capacitor having a first terminal coupled to the second terminal of the first resistor and a second terminal coupled to the second terminal of the inductor;

a second resistor having a first terminal coupled to the second terminal of the first resistor and a second terminal;

a hysteresis comparator having a first input terminal coupled to the second terminal of the first resistor and an output terminal, the hysteresis comparator comparing a first voltage received from the first input terminal thereof with a first and a second threshold voltage; and

a switching control circuit which receives a discrimination result from the output terminal of the hysteresis comparator and controls the control terminals of the MOSFETs based on the discrimination result.

9. The power supply device according to claim 8, further comprising:

a third resistor having a first terminal coupled to the first terminal of the first capacitor and a second terminal;

a fourth resistor having a first terminal coupled to the second terminal of the third resistor and a second terminal coupled to the ground terminal; and

an error amp having a first input terminal which receives a second voltage from the second terminal of the third resistor, a second input terminal which receives a first reference voltage and an output terminal outputting an output signal to a second input terminal of the hysteresis comparator,

wherein the second terminal of the second resistor is coupled to the ground terminal.

10. The power supply device according to claim 8, wherein a predetermined voltage is input to a second terminal of the hysteresis comparator.

11. The power supply device according to claim 8, wherein the second terminal of the second resistor is coupled to the ground terminal.

12. The semiconductor integrated circuit for the power supply device according to claim 8, wherein the hysteresis comparator outputs the discrimination result so as to control the first voltage between the first threshold voltage and the second threshold voltage.