US 2014/0111113 A1Published application

Simplified current sense for buck led driver

AssigneePower Integrations, Inc.

InventorJose R. DEL CARMEN, JR.

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Abstract

A current sense and feedback circuit is provided for a non-isolated Buck power converter to maintain constant current load regulation. The Buck converter may have a high side power switch and may include an input port, a switcher unit including a switch and a controller, an inductor coupled to the output, and a freewheeling diode for circulating the inductor current when the switch is open. The simplified current sense and feedback circuit of the power converter may include a current sense resistor module coupled to the freewheeling diode to provide a sense signal to the controller. The controller may also be coupled to the output of the power converter to sense an over voltage condition. The simplified current sense and feedback circuit may provide output regulation while maintaining a low component count, small size, and low loss that makes the power converter suitable for use in compact design applications.

Claims20

Dependent claims

A feedback sense circuit for a power converter, wherein the power converter transfers current from an input port to a regulated output through an inductor during an on time of a power switch, and wherein current circulates through the inductor and a freewheeling diode during an off time of power switch, and wherein switching of the power switch is controlled by a controller in response to a feedback signal received on a feedback terminal of the controller, the feedback sense circuit comprising:

a sense resistor module comprising a first end and a second end, wherein the first end of the sense resistor module is coupled to a cathode of the freewheeling diode, and wherein the second end of the sense resistor module is coupled to a common coupling point of the inductor and the power switch;
a first resistor comprising a first end and a second end, wherein the first end of the first resistor is coupled to the first end of the sense resistor module, and where the second end of the first resistor is coupled to the feedback terminal of the controller;
and
a first capacitor coupled between the feedback terminal of the controller and the common coupling point of the inductor and the power switch.

1 more element

A power converter for transferring current from an input port to a regulated output, the power converter comprising:

a power switch;
a controller coupled to the power switch, wherein the controller is configured to control switching of the power switch based on a feedback sense signal received at a feedback terminal of the controller;
an inductor comprising a first end and a second end, wherein the first end of the inductor is coupled to the power switch, and wherein the second end of the inductor is coupled to the output of the power converter;
a freewheeling diode having an anode and a cathode, wherein the anode of the freewheeling diode is coupled to the output of the power converter;
and
a current sense circuit comprising:
a sense resistor module comprising a first end and a second end, wherein the first end of the sense resistor module is coupled to the cathode of the freewheeling diode, and wherein the second end of the sense resistor module is coupled to the first end of the inductor;
a first resistor comprising a first end and a second end, wherein the first end of the first resistor is coupled to the first end of the sense resistor module, and where the second end of the first resistor is coupled to the feedback terminal of the controller;
and
a first capacitor coupled between the feedback terminal of the controller and the first end of the inductor.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/654,773Filed 18 Oct 2012
Published: 24 Apr 2014
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

H02M 3/158
With automatic control of output voltage or current, e.g. switching regulators: including plural semiconductor devices as final control devices…
H05B 45/14
Controlling the intensity of the light: using electrical feedback from LEDs or from LED modules
H05B 45/375
Switched mode power supply [SMPS]: using buck topology
H02M 1/0009
Details of control, feedback or regulation circuits: devices or circuits for detecting current in a converter