US 2009/0212716 A1Published application

Light Source Driving Module and Circuit

AssigneeChunghwa Picture Tubes, Ltd.

InventorsChien-Yang Chen, Chi-Hsiu Lin, Shin-Chang Lin, Po-Kun Hsieh

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Abstract

A light source driving circuit includes a voltage signal source and a temperature-improving current source for adjusting luminance of a series of LEDs. A first end of the series of LEDs is electrically connected to a ground end. The temperature-improving current source includes an adjustable power supply for outputting an adjustable voltage, a voltage-controlled current source for outputting currents according to the voltage signal source, and a feedback circuit electrically connected between a second end of the series of the LEDs and the adjustable power supply for controlling the output voltage of the adjustable power supply according to the voltage on the second end of the series of LEDs.

Claims26

Dependent claims

A light source driving circuit for driving a series of Light Emitting Diodes (LEDs), a first end of the series of LEDs electrically connected to a ground end, the light source driving circuit comprising:

a voltage signal source;
a voltage-controlled current source comprising:
a first amplifier comprising:
a positive input end, electrically connected to the voltage signal source;
a negative input end;
and
an output end;
a first BipolarJunction Transistor (BJT), comprising:
an emitter, electrically connected to the negative input end of the first amplifier;
a base, electrically connected to the output end of the first amplifier;
and
a collector;
a first resistor, electrically connected between the negative input end of the first amplifier and the ground end;
a second amplifier comprising:
a positive input end, electrically connected to the collector of the first BJT;
a negative input end;
and
an output end;
a second resistor, electrically connected between the collector of the first BJT and a biasing source;
a third resistor, electrically connected between the negative input end of the second amplifier and the biasing source;
and
a second BJT comprising:
an emitter, electrically connected to the negative end of the second amplifier;
a base, electrically connected to the output end of the second amplifier;
and
a collector, electrically connected to a second end of the series of LEDs.

23 more elements

A light source driving circuit for driving a series of LEDs, a first end of the series of LEDs electrically connected to a ground end, the light source driving circuit comprising:

a voltage signal source;
a current source comprising:
an adjustable biasing source;
a voltage-controlled current source, comprising:
a first amplifier comprising:
a positive input end, electrically connected to the voltage signal source;
a negative input end;
and
an output end;
a first BJT comprising:
an emitter, electrically connected to the negative input end of the first amplifier;
a base, electrically connected to the output end of the first amplifier;
and
a collector;
a first resistor, electrically connected between the negative input end of the first amplifier and the ground end;
a second amplifier comprising:
a positive input end, electrically connected to the collector of the first BJT;
a negative input end;
and
an output end;
a second resistor, electrically connected between the collector of the first BJT and the adjustable biasing source;
a third resistor, electrically connected between the negative input end of the second amplifier and the adjustable biasing source;
a second BJT comprising:
an emitter, electrically connected to the negative input end of the second amplifier;
a base, electrically connected to the output end of the second amplifier;
and
a collector, electrically connected to a second end of the series of the LEDs;
and
a feedback circuit, electrically connected between the second end of the series of the LEDs and the adjustable biasing source for controlling level of an output voltage of the adjustable biasing source according to a voltage on the second end of the series of LEDs.

26 more elements

A light source driving module for driving an array of LEDs, the array of LEDs having K series of LEDs, K being a positive integer, a first end of each series of the LEDs being electrically connected to a ground end, the light source driving module comprising:

a voltage signal source;
K current sources, each of the K current sources comprising:
an adjustable biasing source;
a voltage-controlled current source comprising:
a first amplifier comprising:
a positive input end, electrically connected to the voltage signal source;
a negative input end;
and
an output end;
a first BJT comprising:
an emitter, electrically connected to the negative input end of the first amplifier;
a base, electrically connected to the output end of the first amplifier;
and
a collector;
a first resistor, electrically connected between the negative input end of the first amplifier and the ground end;
a second amplifier comprising:
a positive input end, electrically connected to the collector of the first BJT;
a negative input end;
and
an output end;
a second resistor, electrically connected between the collector of the first BJT and the adjustable biasing source;
a third resistor, electrically connected between the negative input end of the second amplifier and the adjustable biasing source;
a second BJT comprising:
an emitter, electrically connected to the negative input end of the second amplifier;
a base, electrically connected to the output end of the second amplifier;
and
a collector, electrically connected to a second end of the corresponding series of the LEDs;
and
a feedback circuit, electrically connected between the second end of the corresponding series of the LEDs and the adjustable biasing source for controlling level of an output voltage of the adjustable biasing source according to a voltage on the second end of the corresponding series of LEDs.

26 more elements

Dependencies are inferred from the claim text.