Switching regulator

• US 7,868,598 B2
• Filed: 03/09/2006
• Issued: 01/11/2011
• Est. Priority Date: 03/10/2005
• Status: Expired due to Fees

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Ishino, Tsutomu
• Primary Examiner(s): Vu; Bao Q
• Assistant Examiner(s): Tran; Nguyen
• Application Number:
  US11/817,091
• Publication Number:
  US 20090021232A1
• Time in Patent Office: 1,769 Days
• Field of Search: 323/282, 323/242, 323/243, 323/271, 323/288, 323/222, 323/273
• US Class Current: 323/282
• CPC Class Codes: H02M 3/1563 without using an external clock H02M3/158 takes precedence

Abstract

A switching regulator according to the invention includes a resistor (R3) and a capacitor (C3) for generating a ramp signal from the AC component in the output of a hysteresis comparator (1). The switching regulator is characterized in that the hysteresis comparator (1) compares with a reference voltage outputted from a reference voltage source (2) a voltage obtained by superimposing the ramp signal on the divided voltage of the output voltage (V_O) as obtained between resistors (R1 and R2).

Claims

1. A switching circuit for a switching regulator, the switching circuit comprising:

a hysteresis comparator;

a switching element switched based on an output of the hysteresis comparator;

a first terminal arranged to output a signal corresponding to a switching operation of the switching element;

a second terminal arranged to receive an output voltage of the switching regulator;

a first resistor having one end connected to the second terminal and having another end connected to an inverting input terminal of the hysteresis comparator;

a second resistor having one end connected to the other end of the first resistor and having another end connected to a fixed potential;

a first capacitor having one end connected to the second terminal and having another end connected to the inverting input terminal of the hysteresis comparator;

a third resistor having one end connected to the inverting input terminal of the hysteresis comparator; and

a second capacitor having one end connected to another end of the third resistor and having another end connected to an output terminal of the hysteresis comparator,

wherein the hysteresis comparator is arranged to compare a reference voltage with a voltage obtained by superimposing a ramp signal generated from an alternating-current component in an output of the hysteresis comparator by the third resistor and the first capacitor on a divided voltage obtained by dividing the output voltage of the switching regulator with the first resistor and the second resistor.

2. An electrical device including a switching regulator,

wherein the switching regulator is arranged to switch a switching element based on an output of a hysteresis comparator, wherein the switching regulator comprises:

a first resistor having one end connected to a potential of an output voltage of the switching regulator and another end connected to an inverting input terminal of the hysteresis comparator;

a second resistor having one end connected to the other end of the first resistor and having another end connected to a fixed potential;

a first capacitor having one end connected to the potential of the output voltage of the switching regulator and having another end connected to the inverting input terminal of the hysteresis comparator;

a third resistor having one end connected to the inverting input terminal of the hysteresis comparator; and

a second capacitor having one end connected to an other end of the third resistor and having another end connected to an output terminal of the hysteresis comparator,

wherein the hysteresis comparator is arranged to compare a reference voltage with a voltage obtained by superimposing a ramp signal generated from an alternating-current component in an output of the hysteresis comparator by the third resistor and the first capacitor on a divided voltage obtained by dividing the output voltage of the switching regulator with the first resistor and the second resistor.

3. The electrical device of claim 2, wherein the electrical device is a portable device.