Control circuit for detecting a reverse current in a DC-DC converter
First Claim
1. A DC-DC converter performing pulse width modulation or pulse frequency modulation and outputting an output voltage via a choke coil, the DC-DC converter comprising:
- a first transistor receiving an input voltage;
a second transistor coupled to the first transistor, the choke coil being coupled to a node between the first and second transistors;
a drive control circuit, coupled to the first and second transistors, generating a first drive signal and a second drive signal activating and inactivating the first transistor and the second transistor in a complementary manner;
a reversed flow detection circuit detecting current flowing to the second transistor and generating a detection signal controlling activation and inactivation of the second transistor; and
a detection signal invalidation circuit, coupled to the reversed flow detection circuit and the drive control circuit, invalidating the detection signal in response to an operation switch signal during the pulse width modulation.
9 Assignments
0 Petitions
Accused Products
Abstract
A DC-DC converter reducing reverse current and maintaining high conversion efficiency under a light load. The DC-DC converter perform pulse width modulation (PWM) or pulse frequency modulation (PFM) and includes a drive control circuit generating a first drive signal and a second drive signal activating and inactivating a first transistor and a second transistor in a complementary manner. A reversed flow detection circuit detects current flowing to the second transistor and generates a detection signal controlling activation and inactivation of the second transistor. A detection signal invalidation circuit, coupled to the reversed flow detection circuit and the drive control circuit, receiving an operation switch signal and invalidating the detection signal in response to the operation switch signal during at least a certain period of the PWM.
-
Citations
22 Claims
-
1. A DC-DC converter performing pulse width modulation or pulse frequency modulation and outputting an output voltage via a choke coil, the DC-DC converter comprising:
-
a first transistor receiving an input voltage; a second transistor coupled to the first transistor, the choke coil being coupled to a node between the first and second transistors; a drive control circuit, coupled to the first and second transistors, generating a first drive signal and a second drive signal activating and inactivating the first transistor and the second transistor in a complementary manner; a reversed flow detection circuit detecting current flowing to the second transistor and generating a detection signal controlling activation and inactivation of the second transistor; and a detection signal invalidation circuit, coupled to the reversed flow detection circuit and the drive control circuit, invalidating the detection signal in response to an operation switch signal during the pulse width modulation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 21)
-
-
13. A DC-DC converter performing pulse width modulation or pulse frequency modulation and outputting an output voltage via a choke coil, the DC-DC converter comprising:
-
a first transistor receiving an input voltage; a second transistor coupled to the first transistor, the choke coil coupled to a node between the first and second transistors; a drive control circuit, coupled to the first and second transistors, generating a first drive signal and a second drive signal activating and inactivating the first transistor and the second transistor in a complementary manner; and a reversed flow detection circuit detecting current flowing to the second transistor and generating a detection signal controlling activation and inactivation of the second transistor, wherein the reversed flow detection circuit receives an operation switch signal for switching between a pulse width modulation mode and a pulse frequency modulation mode and stops operating when the operation switch signal indicates the pulse width modulation mode.
-
-
14. A control circuit for a DC-DC converter that performs pulse width modulation or pulse frequency modulation and outputs an output voltage via a choke coil, the DC-DC converter including a first transistor receiving an input voltage, and a second transistor coupled to the first transistor, the choke coil being coupled to a node between the first and second transistors;
- the control circuit comprising;
a drive control circuit, coupled to the first and second transistors, generating a first drive signal and a second drive signal activating and inactivating the first transistor and the second transistor in a complementary manner; a reversed flow detection circuit detecting current flowing to the second transistor and generating a detection signal controlling activation and inactivation of the second transistor; and a detection signal invalidation circuit, coupled to the reversed flow detection circuit and the drive control circuit, receiving an operation switch signal in response to the operation switch signal during the pulse width modulation mode. - View Dependent Claims (15, 16, 17, 18, 19, 22)
- the control circuit comprising;
-
20. A control circuit for a DC-DC converter performing pulse width modulation or pulse frequency modulation and outputting an output voltage via a choke coil, the DC-DC converter including a first transistor receiving an input voltage, and a second transistor coupled to the first transistor, the choke coil being coupled to a node between the first and second transistors;
- the control circuit comprising;
a drive control circuit, coupled to the first and second transistors, generating a first drive signal and a second drive signal activating and inactivating the first transistor and the second transistor in a complementary manner; and a reversed flow detection circuit detecting current flowing to the second transistor and generating a detection signal controlling activation and inactivation of the second transistor, wherein the reversed flow detection circuit receives an operation switch signal for switching between a pulse width modulation mode and a pulse frequency modulation mode and stops operation when the operation switch signal indicates the pulse width modulation mode.
- the control circuit comprising;
Specification