Inverter controller with automatic brightness adjustment circuitry

• US 7,095,392 B2
• Filed: 02/07/2003
• Issued: 08/22/2006
• Est. Priority Date: 02/07/2003
• Status: Expired due to Fees

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: Lin, Yung-Lin
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): DHARIA, PRABODH M
• Application Number:
  US10/360,412
• Publication Number:
  US 20040155853A1
• Time in Patent Office: 1,292 Days
• Field of Search: 345/87, 345/88, 345/204, 345/211, 345/102, 345/207, 345/690, 315/82, 315/169.3, 315/291, 315/219, 315/224, 315/307, 356/402, 362/233, 362/260, 250/205, 455/89, 455/90, 363/40
• US Class Current: 345/87
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

An inverter controller for an LCD panel display with automatic brightness adjustment circuitry is provided. In one exemplary embodiment, the controller includes a look-up table that receives a signal indicative of the ambient light around the LCD panel and generates a signal corresponding to desired panel brightness. The signal corresponding to the desired panel brightness is, in turn, used as a threshold signal in a conventional feedback inverter topology supplying power to lamps associated with the LCD panel. In another exemplary embodiment, a master controller is provided that includes a light sensor controller to poll a slave light sensor to generate a signal indicative of the ambient light around the LCD panel.

Claims

1. A master/slave brightness controller for an LCD panel display, comprising:

an optical sensor generating a signal indicative of ambient light around said LCD panel;

a micro controller controlling said optical sensor to generate said signal indicative of ambient light around said LCD panel, said micro controller is also adapted to generate said signal indicative of ambient light around said LCD panel independently of a host system CPU;

a look-up table receiving said signal indicative of ambient light around said LCD panel and adapted to generate a target panel brightness level signal based on said signal indicative of ambient light around said LCD panel;

a low frequency PWM circuit capable of generating a burst mode signal having a pulse width based on said target panel brightness signal; and

an inverter circuit adapted to control power delivered to said LCD panel based on, at least in pan, said burst mode signal;

said inverter circuit is also adapted to control power delivered to said LCD panel independently of a host system CPU.

2. A master/slave brightness controller for an LCD panel display as claimed in claim 1, further comprising an A/D converter circuit receiving said signal indicative of ambient light around said LCD panel and generating a digital signal having a desired bit dept.

3. A master/slave brightness controller for an LCD panel display as claimed in claim 1, wherein said inverter circuit selected from the group consisting of full bridge, half bridge, push pull, royer and class D inverter circuits.

4. A master/slave brightness controller for ar LCD panel display as claimed in claim 1, said LCD panel comprising a plurality of lamps receiving power from at least one said inverter circuit.

5. A master/slave brightness controller for an LCD panel display as claimed in claim 1, wherein said look-up table comprising a register of input values and corresponding output values, said input values represented by said signal indicative of ambient light around said LCD panel and said output values represented by said plurality of target panel brightness level signals.