Multi-output power supply circuit

• US 20060131961A1
• Filed: 11/18/2005
• Published: 06/22/2006
• Est. Priority Date: 11/19/2004
• Status: Abandoned Application

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yoshida, Masato, Shigemi, Tomoya, Tanabe, Hirohisa, Akashi, Hiroki, Ishimaru, Makoto, Motomori, Mikio, Ishii, Takuya, Ryu, Takashi
• Application Number:
  US11/283,582
• Publication Number:
  US 20060131961A1
• Time in Patent Office: Days
• US Class Current: 307/31
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/008 Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators
• CPC Class Codes: H02M 1/009 having two or more independently controlled outputs for DC-DC converter with intermediate AC H02M3/33561
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load

Abstract

A multi-output power supply circuit comprising a switching circuit 10 having a series circuit of a high-side switch 11 and a low-side switch 12, connected in parallel with an input DC power supply 1, and a step-down control circuit 13, and multiple step-up circuits 20 and 30 connected to the output terminal of the switching circuit, wherein each step-up circuit has an inductor connected to the output terminal of the switching circuit, a step-up switch, a step-up rectifier, smoothing means for outputting an output DC voltage, and a step-up control circuit for driving the step-up switch.

Claims

1. A multi-output power supply circuit comprising:

a switching circuit having a series circuit of a high-side switch and a low-side switch, which are connected in parallel with an input DC power supply, and a step-down control circuit for alternately opening/closing said high-side switch and said low-side switch, and

multiple step-up circuits each connected to the connection point of said high-side switch and said low-side switch.

2. The multi-output power supply circuit in accordance with claim 1, wherein said step-up circuit comprises:

an inductor, one terminal of which is connected to the connection point of said high-side switch and said low-side switch,

a step-up switch and a step-up rectifier connected to the other terminal of said inductor,

smoothing means, connected to said step-up rectifier, for outputting an output DC voltage, and

a step-up control circuit for controlling the ON/OFF operation of said step-up switch so as to control said output DC voltage.

3. The multi-output power supply circuit in accordance with claim 1, wherein said step-down control circuit and said step-up control circuit drive said high-side switch and said low-side switch, and said step-up switch, respectively, at the same switching frequency.

4. The multi-output power supply circuit in accordance with claim 1, wherein said step-down control circuit is configured that the ratio of the ON time with respect to the switching cycle of said high-side switch is set so as to be equal to or less than the ratio of the minimum value of the output DC voltages output from said multiple step-up circuits with respect to the input voltage output from said input DC power supply.

5. A multi-output power supply circuit comprising:

a switching circuit having a series circuit of a high-side switch and a low-side switch, which are connected in parallel with an input DC power supply, and a step-down control circuit for alternately opening/closing said high-side switch and said low-side switch,

a smoothing circuit, connected to the connection point of said high-side switch and said low-side switch, for outputting a first output DC voltage, and

at least one step-up circuit connected to the connection point of said high-side switch and said low-side switch.

6. The multi-output power supply circuit in accordance with claim 5, wherein said step-up circuit comprises:

an inductor, one terminal of which is connected to the connection point of said high-side switch and said low-side switch,

a step-up switch and a step-up rectifier connected to the other terminal of said inductor,

smoothing means, connected to said step-up rectifier, for outputting an output DC voltage, and

a step-up control circuit for controlling the ON/OFF operation of said step-up switch so as to control said output DC voltage.

7. The multi-output power supply circuit in accordance with claim 5, wherein said smoothing circuit comprises an inductor, one terminal of which is connected to the connection point of said high-side switch and said low-side switch, and a capacitor connected to the other terminal of said inductor so as to output said first output DC voltage from across said capacitor.

8. The multi-output power supply circuit in accordance with claim 5, wherein said step-down control circuit controls the ON/OFF operation of said high-side switch and said low-side switch so as to control said first output DC voltage.

9. The multi-output power supply circuit in accordance with claim 6, wherein said step-down control circuit and said step-up control circuit drive said high-side switch and said low-side switch, and said step-up switch, respectively, at the same switching frequency.