How to avoid working voltage jitter during programming from affecting writing high voltage

Abstract

The invention provides a method for preventing the prog high voltage from being influenced by jittering of the working voltage during programming. When reference voltage is built, the reference voltage is firstly transmitted to a maintaining capacitor. When a charge pump works, in order to prevent the reference voltage from being influenced by jittering of the working voltage, the maintaining capacitor is isolated from a reference voltage generating circuit by switching off a control switch to isolate the working voltage from the input reference voltage generated by the reference voltage generating circuit, the voltage of the charge pump is provided by the input reference voltage, then the stable prog high voltage is formed, the output reference voltage is provided by the maintaining capacitor, and jittering of the prog high voltage is restrained.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing and testing, in particular to a method for avoiding the influence of writing high voltage from working voltage jitter during programming. Background technique [0002] When performing operations such as programming on the flash memory (Flash), there will be a large current output from the low dropout linear regulator (Low Dropout Regulator) to the voltage pump (Charge pump). The boost voltage generated by the voltage pump is used to program the flash memory. Usually, the voltage pump needs to generate a write high voltage (Prog HV) through the reference voltage Vref. [0003] If a capless low dropout linear regulator is used, the operating voltage Vdd of the flash memory will experience a large voltage drop. When the operating voltage Vdd fluctuates greatly, it will cause the reference voltage Vref to fluctuate, which will cause damage to the flash memory. The write high voltage requir...

AI Technical Summary

Problems solved by technology

[0003] If a capless low dropout linear regulator is used, the operating voltage Vdd of the flash memory will experience a large voltage drop. When the operating voltage Vdd fluctuates greatly, it will cause the reference voltage Vref to fluctuate, which will cause damage to the flash memory. The write high voltage required for programming is unstable, resulting in programming errors

[0004] Specifically, please refer to figure 1 , figure 1 It is a schematic diagram of the circuit structure when programming the flash memory in the prior art, wherein, when the flash memory is programmed, if the working voltage Vdd fluctuates, it will cause the reference voltage Vref to fluctuate correspondingly, which will affect the writing high voltage and make the writing High voltage usually presents jitter

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