Low power consumption constant current and backlight control circuit and TV

Abstract

The invention discloses a low-power-consumption constant-current and backlight control circuit. The low-power-consumption constant-current and backlight control circuit comprises a front-end power supply circuit and a rear-end linear constant-current circuit, wherein the front-end power supply circuit comprises a power supply circuit and a feedback adjusting circuit; the rear-end linear constant-current circuit is provided with a connecting reference signal input end which is used for connecting constant-current reference voltage and for conducting / disconnecting the connection between the rear-end linear constant-current circuit and an LED (Light Emitting Diode) lamp string to be supplied with power according to the constant-current reference voltage; a loop of voltage acquisition output end is led out through a voltage detection circuit from the connecting position of the rear-end linear constant-current circuit and the LED lamp string to be supplied with power to acquire the voltage at the connecting position, the voltage value of a control signal input end is adjusted according to the acquisition result, the voltage detection circuit comprises a diode and a pull-up resistor, a cathode of the diode is connected with the cathode of the LED lamp string, an anode of the diode is connected with one end of the pull-up resistor and the other end of the pull-up resistor is connected with a high level; the anode of the diode is connected with the voltage acquisition output end.

Description

technical field [0001] The invention relates to the technical field of power supply control, in particular to a low power consumption constant current and backlight control circuit and a television set with the low power consumption constant current and backlight control circuit. Background technique [0002] The linear constant current modulation circuit is a unit circuit widely used in analog integrated circuits, and has a wide range of applications in practice. Among them, in the field of power control technology of LED TVs, the front-end circuit is often used to output a constant voltage, and the back-end circuit is used to realize step-up or step-down constant current to realize power supply to the main board of the TV set and the LED backlight. [0003] In the process of integrating TV components, TV motherboards and backlight strips usually need to be produced together, and different numbers of backlight LED strips will require linear constant current modulation circu...

AI Technical Summary

Problems solved by technology

When the linear constant current circuit works, the voltage at both ends of the switching tube will be due to the voltage error of the LED light string (generally, the range of a single LED is 2.8 to 3.4, due to the series connection of multiple LED lights, the difference between the upper limit and the lower limit of the voltage range of the LED light string will be relatively large), due to the influence of the intermodulation of the transformer (the general range is 7%), the higher the voltage, the greater the power consumption, which will cause the cost of the device to increase and the circuit efficiency to decrease

In addition, in order to reduce the temperature of the switching tube, the general switching tube will be used in parallel with multiple mos tubes or triodes, which leads to an increase in cost

Images