Semiconductor integrated circuit and method for operating the same for a stabilizing power supply

Patent metadata

Field	Value
Publication number	US-9600005-B2
Application number	US-201514593912-A
Country	US
Kind code	B2
Filing date	Jan 9, 2015
Priority date	Jan 17, 2014
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

A semiconductor integrated circuit that is used for a stabilizing power supply circuit which supplies an output power supply voltage to a parallel connection of a smoothing capacitor and a load, from an input power supply voltage, includes an error amplifier that detects an error of the output power supply voltage, an output control circuit that is connected between the input terminal and the output terminal, a phase compensation circuit that is connected to the error amplifier, and a detection control circuit that is connected to the phase compensation circuit.

First claim

What is claimed is:

1. A semiconductor integrated circuit that is used for a stabilizing power supply circuit which supplies an output power supply voltage to a parallel connection of a smoothing capacitor and a load which are connected to an output terminal from an input power supply voltage which is supplied to an input terminal, comprising:
an error amplifier that detects an error of the output power supply voltage;
an output control circuit that is connected between the input terminal and the output terminal;
a phase compensation circuit that is connected to the error amplifier; and
a detection control circuit that is connected to the phase compensation circuit, wherein
the output control circuit is controlled by the error amplifier responding to the error of the output power supply voltage, thereby generating the output power supply voltage, and
the detection control circuit detects temperature variation of the smoothing capacitor and resistance variation of an equivalent series resistance of the smoothing capacitor due to the temperature variation, and variably controls the phase compensation circuit according to the detected result.

2. The semiconductor integrated circuit according to claim 1 , wherein
in a state where the temperature of the smoothing capacitor is lower than a predetermined temperature, the detection control circuit sets a time constant of the phase compensation circuit to a smaller time constant than a predetermined time constant, and
in a state where the temperature of the smoothing capacitor is higher than the predetermined temperature, the detection control circuit sets the time constant of the phase compensation circuit to another time constant larger than the predetermined time constant.

3. The semiconductor integrated circuit according to claim 2 , wherein
in a state where the temperature of the smoothing capacitor is lower than the predetermined temperature, a pole frequency that is set by phase compensation of the small time constant is set to a higher frequency than a predetermined frequency, and
in a state where the temperature of the smoothing capacitor is higher than the predetermined temperature, a pole frequency that is set by phase compensation of the large time constant is set to a lower frequency than the predetermined frequency.

4. The semiconductor integrated circuit according to claim 3 , wherein
the detection control circuit detects the temperature variation or the resistance variation of the equivalent series resistance of the smoothing capacitor, in at least four stages, thereby variably controlling phase compensation characteristics of the phase compensation circuit in at least four stages.

5. The semiconductor integrated circuit according to claim 4 , wherein
the detection control circuit performs an A/D conversion that determines an analog input signal having the temperature variation or the resistance variation as at least four multi-value levels, using at least three reference values.

6. The semiconductor integrated circuit according to claim 5 , wherein
the A/D conversion is performed by any one of a flash type A/D converter, a sequential comparison type A/D converter, and a pipeline type A/D converter.

7. The semiconductor integrated circuit according to claim 4 , wherein
the detection control circuit uses a rate of change of a forward voltage drop of a PN junction diode with respect to temperature, thereby detecting variation of the temperature of the smoothing capacitor which is ambient temperature of the stabilizing power supply circuit.

8. The semiconductor integrated circuit according to claim 4 , wherein
the detection control circuit detects variation of a voltage amplitude level of a ripple voltage included in the output power supply voltage, thereby detecting the resistance variation of the equivalent series resistance of the smoothing capacitor due to the temperature variation.

9. The semiconductor integrated circuit according to claim 4 , wherein
a smoothing coil of a low pass filter is connected between the output terminal, and the parallel connection of the smoothing capacitor and the load,
the output control circuit includes a first switching element that is connected between the input terminal and the output terminal, and a second switching element that is connected between the output terminal and a ground voltage,
the semiconductor integrated circuit further includes a switching control circuit that controls switching of the first switching element and the second switching element of the output control circuit, according to an error detection output signal of the error amplifier,
a period in which the first switching element is controlled so as to be in an ON state and the second switching element is controlled so as to be in an OFF state, by the switching control circuit is an ON period in which magnetic energy is accumulated in the smoothing coil of the low pass filter,
a period in which the first switching element is controlled so as to be in an OFF state and the second switching element is controlled so as to be in an ON state, by the switching control circuit is an OFF period in which the magnetic energy accumulated in the smoothing coil of the low pass filter is consumed, and
the switching control circuit respectively sets the ON period and the OFF period to a predetermined value according to the error detection output signal of the error amplifier, and thereby the output power supply voltage that is dropped to a voltage lower than the input power supply voltage is generated by the stabilizing power supply circuit.

10. The semiconductor integrated circuit according to claim 4 , wherein
one end of a smoothing coil is connected to the input terminal to which the input power supply voltage is supplied, and the other end of the smoothing coil is connected to the output control circuit,
the output control circuit includes a first switching element that is connected between the other end of the smoothing coil and the output terminal, and a second switching element that is connected between the other end of the smoothing coil and a ground voltage,
the semiconductor integrated circuit further includes a switching control circuit that controls switching of the first switching element and the second switching element of the output control circuit, according to an error detection output signal of the error amplifier,
a period in which the second switching element is controlled so as to be in an ON state and the first switching element is controlled so as to be in an OFF state, by the switching control circuit is an ON period in which magnetic energy is accumulated in the smoothing coil,
a period in which the second switching element is controlled so as to be in an OFF state and the first switching element is controlled so as to be in an ON state, by the switching control circuit is an OFF period in which the magnetic energy accumulated in the smoothing coil is consumed, and
the switching control circuit respectively sets the ON period and the OFF period to the predetermined value according to the error detection output signal of the error amplifier, and thereby the output power supply voltage that is boosted to a voltage higher than the input power supply voltage is generated by the stabilizing power supply circuit.

11. The semiconductor integrated circuit according to claim 4 , wherein
the output terminal is connected to the parallel connection of the smoothing capacitor and the load, and
the stabilizing power supply circuit operates as a series regulator in which a voltage drop of the output control circuit is adjusted by the error detection output signal of the error amplifier in such a manner th

Assignees

• Renesas Electronics Corp

Inventors

• Hayashi Kentaro
• Hayashi Yutaka

Classifications

• H02M3/156

  with automatic control of output voltage or current, e.g. switching regulators · CPC title

• H02M1/14

  Arrangements for reducing ripples from DC input or output · CPC title

• G05F1/56

  using semiconductor devices in series with the load as final control devices (G05F1/461 takes precedence) · CPC title

• G05F1/567 Primary

  for temperature compensation · CPC title

• H02M2001/0025

  Electricity · mapped topic