# US 12,002,396 B2 · Power management circuit and timing controller for display device

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- Number: US 12,002,396 B2
- Document ID: US12002396B2
- Status: Granted
- Kind: B2
- Application number: 17/552,260
- Filed: 2021-12-15
- Published: 2022-06-23
- Granted: 2024-06-04
- Earliest claimed: 2020-12-18
- Assignees: Lx Semicon Co., Ltd.
- Applicants: LX Semicon Co., Ltd.
- Inventors: Yang Sun
- Web page: https://patentgrep.com/patent/US12002396B2

## CPC

- G09G 3/20: for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix {no fixed position being assigned to or needed to be assigned to the individual characters or partial characters}
- G06F 1/3265: {Power saving in display device}
- G06F 1/3287: by switching off individual functional units in the computer system
- G09G 3/3611: {Control of matrices with row and column drivers}
- G09G 2310/08: Details of timing specific for flat panels, other than clock recovery
- G09G 2330/021: Power management, e.g. power saving
- G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

The present embodiment relates to a power management circuit and timing controller for a display device. The power management circuit optimizes power consumption by receiving analysis information from a timing controller capable of analyzing image data and changing an operating condition for a power conversion circuit based on the analysis information.

## Claims

### Claim 1

A power management circuit connected to a power conversion circuit and a timing controller, comprising:
a switch driving circuit configured to drive a plurality of power switches connected to the power conversion circuit; and
a control circuit configured to receive a control signal from the timing controller and to change a driving condition for the switch driving circuit in response to the control signal, wherein
the plurality of power switches has different channel widths,
the control signal includes information on the size of a panel load,
the control circuit is configured to select at least one power switch based on the size of the panel load and the channel width of each of one or more power switches, and to drive the selected power switch, and
the control circuit is configured to control a bias current of an amplifier configured to supply a voltage to a common electrode of a panel in response to the control signal;
wherein the plurality of power switches comprises a first power switch and a second power switch having a channel width wider than that of the first power switch, and
the size of the second power switch is larger than the size of the first power switch,
in case the size of the panel load is a first value, the control circuit is configured to drive the first power switch and is configured not to drive the second power switch,
in case the size of the panel load is a second value, the control circuit is configured not to drive the first power switch and is configured to drive the second power switch,
in case the size of the panel load is a third value, the control circuit is configured to drive both the first power switch and the second power switch,
the first value is smaller than the second value, and
the second value is smaller than the third value.

### Claim 2 (depends on 1)

The power management circuit of claim 1, wherein:
the plurality of power switches is connected in parallel, and
the control circuit is configured to adjust the number of power switches driven in response to the control signal.

### Claim 3 (depends on 2)

The power management circuit of claim 2, wherein:
the control circuit is configured to decrease the number of driven power switches as the size of the panel load is decreased.

### Claim 4 (depends on 1)

The power management circuit of claim 1, wherein the control circuit is configured to adjust a switching frequency of the at least one power switch in response to the control signal.

### Claim 5 (depends on 1)

The power management circuit of claim 1, wherein:
the plurality of power switches comprises a first power switch and a second power switch having a channel width wider than that of the first power switch,
the control circuit is configured to drive the second power switch when the size of the panel load is greater than a reference value and drive only the first power switch when the size of the panel load is smaller than the reference value.

### Claim 6 (depends on 1)

The power management circuit of claim 1, wherein:
the plurality of power switches comprises a first power switch and a second power switch having a channel width wider than that of the first power switch,
the control signal comprises data of two bits, and
the control circuit is configured to determine whether to drive the second power switch based on a first bit value of the data and determine whether to drive the first power switch based on a second bit value of the data.

### Claim 7 (depends on 1)

The power management circuit of claim 1, wherein power converted by the at least one power switch is supplied to a source driver configured to drive a pixel of the panel.

### Claim 8 (depends on 1)

The power management circuit of claim 1, wherein:
the control signal comprises information on the size of a change of image data between frames, and
the control circuit is configured to control the amplifier such that the bias current is increased as the change size is increased.

### Claim 9 (depends on 1)

The power management circuit of claim 1, wherein the power management circuit is configured to adjust the number of power switches driven in response to the control signal.

### Claim 10 (depends on 1)

The power management circuit of claim 1, wherein the switch driving circuit is configured to sense a feedback voltage, corresponding to an output voltage, through a feedback resistor and the switch driving circuit is configured to drive the at least one power switch in response to the feedback voltage.

### Claim 11 (depends on 1)

The power management circuit of claim 1, wherein the switch driving circuit is configured to sense a current flowing into the at least one power switch through a current sensor connected in series with the at least one power switch and is configured to drive the at least one power switch in response to the current.

### Claim 12 (depends on 2)

The power management circuit of claim 2, wherein the control circuit is configured to increase the number of driven power switches as the size of a panel load is increased.

### Claim 13

A method comprising:
using a switch driving circuit, driving a plurality of power switches connected to a power conversion circuit;
receiving at a control circuit a control signal from a timing controller;
using the control circuit, changing a driving condition for the switch driving circuit in response to the control signal, wherein
the plurality of power switches has different channel widths,
the control signal includes information on the size of a panel load,
the method comprises, using the control circuit, selecting at least one power switch based on the size of the panel load and the channel width of each of one or more power switches, and driving the selected power switch, and
the method comprises, using the control circuit, controlling a bias current of an amplifier configured to supply a voltage to a common electrode of a panel in response to the control signal;
wherein the plurality of power switches comprises a first power switch and a second power switch having a channel width wider than that of the first power switch, and
the size of the second power switch is larger than the size of the first power switch,
in case the size of the panel load is a first value, the control circuit is configured to drive the first power switch and is configured not to drive the second power switch,
in case the size of the panel load is a second value, the control circuit is configured not to drive the first power switch and is configured to drive the second power switch,
in case the size of the panel load is a third value, the control circuit is configured to drive both the first power switch and the second power switch,
the first value is smaller than the second value, and
the second value is smaller than the third value.