Current mode switching regulator with predetermined on time

• US 7,250,746 B2
• Filed: 03/30/2005
• Issued: 07/31/2007
• Est. Priority Date: 03/31/2004
• Status: Expired due to Fees

• Current Assignee: Collabo Innovations, Inc. (Wi-LAN Inc.)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ishii, Takuya, Ryu, Takashi, Akashi, Hiroki, Tanaka, Takeshi, Oswald, Richard K., Yamamoto, Tamotsu, Saito, Hiroshi
• Primary Examiner(s): Laxton, Gary L
• Application Number:
  US11/092,814
• Publication Number:
  US 20050218877A1
• Time in Patent Office: 853 Days
• Field of Search: 323/220, 323222-225, 323/282, 323/284, 323/285, 323/286
• US Class Current: 323/284
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators

Abstract

A power supply switching regulator including a common terminal; an input terminal for supplying a direct current input; an output terminal; a recirculating diode having a first terminal connected to the common terminal; an inductor having a first terminal connected to a second terminal of the recirculation diode and a second terminal connected to the output terminal; a capacitor having a first terminal connected to the output terminal and a second terminal connected to the common terminal; a switch connected between the input terminal and the first terminal of the inductor, the switch operable for switching between an ON state in which the direct current input is coupled to the inductor, and an OFF state in which the direct current input is isolated from the inductor; and a controller coupled to the switch and operable for controlling the amount of time the switch is in the ON state and the OFF state such that the duration of time the switch is in the ON state is inversely proportional to the difference between the voltage at the input terminal and the voltage at the output terminal.

Claims

1. A power supply switching regulator comprising:

a common terminal;

an input terminal for supplying a direct current input;

an output terminal;

a recirculation diode having a first terminal connected to the common terminal;

an inductor having a first terminal connected to a second terminal of the recirculation diode and a second terminal connected to the output terminal;

a capacitor having a first terminal connected to the output terminal and a second terminal connected to the common terminal;

a switch connected between the input terminal and the first terminal of the inductor, said switch operable for switching between an ON state in which said direct current input is coupled to said inductor, and an OFF state in which said direct current input is isolated from said inductor; and

a controller coupled to said switch and operable for controlling the amount of time said switch is in said ON state and the said OFF state such that the duration of time said switch is in said ON state is inversely proportional to the difference between the voltage at the input terminal and the voltage at the output terminal, and

an amplifier having an inverting input coupled to said second terminal of said recirculation diode;

a non-inverting input coupled to a first terminal of an offset voltage source; and

an output coupled to said recirculation diode and to said controller, said first terminal of said recirculation diode being coupled to a second terminal of said offset voltage source.

2. The power supply switching regulator of claim 1, wherein said switching regulator allows for said switch to be in said ON state for duty cycles up to 100%.

3. The power supply switching regulator of claim 1, wherein said recirculation diode comprises a transistor and a body diode, said transistor having a drain terminal coupled to a cathode terminal of said body diode and a source terminal coupled an anode terminal of said body diode.

4. The power supply switching regulator of claim 1, wherein said controller includes a timer circuit operable for controlling the period said switch is in said ON state.

5. The power supply switching regulator of claim 1, wherein said controller operates to power OFF inactive components of said power supply switching regulator during normal operation of said power supply switching regulator.

6. A power supply switching regulator comprising:

a common terminal;

an input terminal for supplying a direct current input;

an output terminal;

a recirculation diode having a first terminal connected to the common terminal;

an inductor having a first terminal connected to a second terminal of the recirculation diode and a second terminal connected to the output terminal;

a capacitor having a first terminal connected to the output terminal and a second terminal connected to the common terminal;

a switch connected between the input terminal and the first terminal of the inductor, said switch operable for switching between an ON state in which said direct current input is coupled to said inductor, and an OFF state in which said direct current input is isolated from said inductor;

a controller coupled to said switch and operable for controlling the amount of time said switch is in said ON state and the said OFF state such that the duration of time said switch is in said ON state is inversely proportional to the difference between the voltage at the input terminal and the voltage at the output terminal;

said controller including a timer circuit operable for controlling the period said switch is in said ON state;

wherein said power supply switching regulator is operable in both a discontinuous inductor current mode and a continuous inductor current mode, and said timer circuit is operable for reducing the amount of time said switch is in the ON state when operating in continuous inductor current mode relative to the amount of time said switch is in the ON state when operating in the discontinuous inductor current mode, at the same values of input voltage, output voltage and load.

7. The power supply switching regulator of claim 6, wherein said timing circuit reduces the period of the ON state of the switch to approximately ninety percent of that when said switching regulator is operating in the continuous inductor current mode relative to when said switching regulator is operating at the same conditions but in discontinuous inductor current mode.

8. The power supply switching regulator of claim 6, wherein the transition between operating in the discontinuous inductor current mode and the continuous inductor current mode, and the transition between operating in the continuous inductor current mode and the discontinuous inductor current mode is performed automatically.

9. A power supply switching regulator comprising:

a common terminal;

an input terminal for supplying a direct current input;

an output terminal;

a recirculation diode having a first terminal connected to the common terminal;

an inductor having a first terminal connected to a second terminal of the recirculation diode and a second terminal connected to the output terminal;

a capacitor having a first terminal connected to the output terminal and a second terminal connected to the common terminal;

a switch connected between the input terminal and the first terminal of the inductor, said switch operable for switching between an ON state in which said direct current input is coupled to said inductor, and an OFF state in which said direct current input is isolated from said inductor; and

a controller coupled to said switch and operable for controlling the amount of time said switch is in said ON state and the said OFF state such that the duration of time said switch is in said ON state is inversely proportional to the difference between the voltage at the input terminal and the voltage at the output terminal,

wherein said controller comprises a loop filter for generating an output voltage, said controller operative for transitioning between a continuous inductor current mode and a discontinuous inductor current mode in accordance with an output voltage level of said loop filter.

10. The power supply switching regulator of claim 9, wherein said controller further comprises an error amplifier having a first input for receiving a signal representing the output voltage level of said power supply switching regulator and a second input for receiving a reference voltage signal, said error amplifier generating an output signal which is coupled to an input of said loop filter.

11. The power supply switching regulator of claim 10, wherein said error amplifier is operable when said power switching regulator is operating in a discontinuous inductor current mode and when said power switching regulator is operating in a continuous inductor current mode.

12. The power supply switching regulator of claim 10, wherein said controller further comprises a comparator having a first input for receiving said signal representing the output voltage level of said power supply switching regulator and a second input for receiving said reference voltage signal, said comparator generating a signal operative for transitioning said switch to said ON state when said signal representing the output voltage level of said power supply falls below said reference voltage signal.

13. The power supply switching regulator of claim 12, wherein continuous direct real time monitoring of an output signal of said comparator is performed so as to reduce effects of an error amplifier filter slew rate and clock period on a transient response of said regulator.

14. The power supply switching regulator of claim 12, wherein said error amplifier and said comparator are formed utilizing a dual output error amplifier.

15. The power supply switching regulator of claim 14, wherein said dual output error amplifier has a first output signal and a second output signal, said first output signal being utilized for generating said output signal coupled to said input of said loop filter, and said second output signal being utilized for driving said comparator, and wherein said first output signal has a voltage response which is modified by said loop filter so as to alter the slew rate of the first output signal.

16. A power supply switching regulator comprising:

a common terminal;

an input terminal for supplying a direct current input;

an output terminal;

a recirculation diode having a first terminal connected to the common terminal;

an inductor having a first terminal connected to a second terminal of the recirculation diode and a second terminal connected to the output terminal;

a capacitor having a first terminal connected to the output terminal and a second terminal connected to the common terminal;

a switch connected between the input terminal and the first terminal of the inductor, said switch operable for switching between an ON state in which said direct current input is coupled to said inductor, and an OFF state in which said direct current input is isolated from said inductor; and

a controller coupled to said switch and operable for controlling the amount of time said switch is in said ON state and the said OFF state such that the duration of time said switch is in said ON state is inversely proportional to the difference between the voltage at the input terminal and the voltage at the output terminal,

wherein a signal representing the voltage at the output terminal of said power supply switching regulator is generated by averaging an input voltage to said inductor.