Control chip with detection function of fly-back-type LED constant current driver

Abstract

The invention discloses a control chip with the detection function of a fly-back-type LED constant current driver. The control chip comprises a power supply and standard module, a current sampling and PWM generating module, a protection and control sampling module, a logic and driving module and a test module. The test module comprises a bias current detecting circuit, an enable signal TM_true generating circuit, a zone bit generating circuit, a voltage selection signal generating circuit and a reference voltage detection circuit. Corresponding input signals are provided for pins outside the chip and according to a testing result, the corresponding pins outside the chip are detected so that a testing result can be obtained; compared with the prior art, full-parameter testing is not needed any more, testing cost of the chip is reduced, a testing method is simplified, and the cost and period of chip testing are greatly saved.

Description

technical field [0001] The invention belongs to the technical field of LED constant current drive control, and in particular relates to a control chip for a flyback LED constant current driver with a detection function. Background technique [0002] At present, the LED constant current driver mostly adopts the flyback circuit structure, such as figure 1 As shown, its internal control chip mainly includes power supply and reference module, current sampling and PWM generation module, protection and control sampling module, and logic and driving module; among them: the power supply and reference module is powered on in sequence according to the power-on sequence of the entire chip, and The external line voltage is stabilized to the internal 5V power supply voltage, which is supplied to other modules respectively. After the chip is powered on and works normally, the reference signal generation circuit inside the module (such as figure 2 shown) to generate different bias curren...

AI Technical Summary

Problems solved by technology

[0005] With the improvement of chip technology, the chip area continues to decline. When the chip shipments are large enough, the manufacturing cost of a single chip continues to drop. The traditional chip test technology is upgraded due to the increase in the complexity of ATE testing, resulting in the existing post-package test. Rising costs increase the complexity of chip peripheral test systems

At the same time, due to the use of full-parameter testing in traditional chip testing, this method requires high chip testing costs and a long time period; for LED driver chips, the chip yield can reach about 95%. Test the key parameters inside the chip to determine whether the chip is good or bad

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