Switching Regulator

• US 20090021232A1
• Filed: 03/09/2006
• Published: 01/22/2009
• Est. Priority Date: 03/10/2005
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Ishino, Tsutomu
• Granted Patent: US 7,868,598 B2
• Time in Patent Office: Days
• US Class Current: 323/288
• 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 outputting a signal corresponding to switching operation of the switching element;

a second terminal receiving an output voltage of the switching regulator; and

a resistor and a capacitor generating a ramp signal from an alternating-current component in the output of the hysteresis comparator,

wherein the hysteresis comparator compares with a reference voltage a voltage obtained by superimposing the ramp voltage on a voltage based on the output voltage of the switching regulator.

2. A switching regulator that switches a switching element based on an output of a hysteresis comparator, the switching regulator comprising:

a resistor and a capacitor generating a ramp signal from an alternating-current component in the output of the hysteresis comparator,

wherein the hysteresis comparator compares with a reference voltage a voltage obtained by superimposing the ramp voltage on a voltage based on an output voltage of the switching regulator.

3. The switching regulator of claim 2, further comprising:

a resistor voltage division circuit dividing the output voltage of the switching regulator; and

a coupling capacitor providing alternating-current coupling between one end of the resistor and an output terminal of the hysteresis comparator,

wherein the other end of the resistor is connected to a voltage division point in the resistor voltage division circuit, and the capacitor is connected in parallel to a voltage division resistor in the resistor voltage division circuit.

4. The switching regulator of claim 3,

wherein the voltage division resistor connected in parallel to the capacitor is provided between an output terminal outputting the output voltage of the switching regulator and the voltage division point in the resistor voltage division circuit.

5. An electrical device including a switching regulator,

wherein the switching regulator switches a switching element based on an output of a hysteresis comparator,

the switching regulator comprises a resistor and a capacitor generating a ramp signal from an alternating-current component in the output of the hysteresis comparator, and

the hysteresis comparator compares with a reference voltage a voltage obtained by superimposing the ramp voltage on a voltage based on the output voltage of the switching regulator.

6. The electrical device of claim 5,

wherein the switching regulator further comprises:

a resistor voltage division circuit dividing the output voltage of the switching regulator; and

a coupling capacitor providing alternating-current coupling between one end of the resistor and an output terminal of the hysteresis comparator, and

the other end of the resistor is connected to a voltage division point in the resistor voltage division circuit, and the capacitor is connected in parallel to a voltage division resistor in the resistor voltage division circuit.

7. The electrical device of claim 6,

wherein the voltage division resistor connected in parallel to the capacitor is provided between an output terminal outputting the output voltage of the switching regulator and the voltage division point in the resistor voltage division circuit.

8. The electrical device of claim 5,

wherein the electrical device is a portable device.

9. The electrical device of claim 6,

wherein the electrical device is a portable device.

10. The electrical device of claim 7,

wherein the electrical device is a portable device.