Voltage test chip: working principle of low voltage detection RESET IC

Date：2021-12-20 17:20:53Views：1697

With the rapid development of modern 5g, Internet of vehicles and other technologies, the signal transmission speed is faster and faster, and the power supply voltage of integrated circuit chip is smaller and smaller. The power supply of early chips was usually 5V and 3.3V, but now the power supply voltage of high-speed IC has reached 2.5V, 1.8V or 1.5V, and the nuclear voltage of some chips has even reached 1V. The smaller the supply voltage of the chip, the more severe the tolerance of voltage fluctuation becomes. How should the chip measure the voltage?

1. If it is broken, the most common is breakdown damage. You can use a multimeter to measure the resistance or voltage of the power supply end of the chip to the ground. Generally, if it is within tens of ohms or the power supply voltage is lower than the normal value, most of it can be regarded as breakdown damage. You can disconnect the power supply end and measure whether the power supply is normal. If the measured resistance is large, it is likely that other ports are damaged. You can also measure other ports one by one. See if there is a port shorted to ground.

2. A multimeter does not have the ability to detect IC. Generally, the multimeter is used to detect the pin voltage when in use and make an approximate judgment, which is not reliable. And make judgment under the condition of being very familiar with this IC.

When the voltage of the built-in low-voltage reset circuit is different from the application specification, the reset circuit of the external low-voltage detection IC can be selected.

• it can provide low-voltage reset function, which needs to cooperate with external simple RC reset circuit or high anti-interference RC reset circuit to achieve complete reset function.

• the recommended values of rres, CRES, RN and CN are the same as simple RC reset circuit and high anti-interference RC reset circuit.

• the position and wiring requirements of CRES (for simple RC reset circuit) and CN (for high anti-interference RC reset circuit) on PCB are the same as those of simple RC reset circuit and high anti-interference RC reset circuit.

Internal POR circuit and internal low voltage reset circuit

• in order to enhance the protection integrity of MCU and simplify the design and cost of external application circuit, power on reset (POR) circuit and low voltage reset (LVR) circuit are provided inside MCU.

• POR circuit is mainly a set of built-in reset circuits with low RC time constant, which has the function of generating reset when powered on. For the initialization action inside MCU, except that the to and PDF flags are cleared to "0", other states are the same as res reset. When using this reset function, because the por time constant is small, in order to make the por operate normally, the power rise speed should be as fast as possible.

• the main function of LVR circuit is that when VDD is less than a specific voltage (depending on the specification) and the duration is greater than 1ms, LVR will be activated, and its initialization action to MCU is the same as res reset.

The above is the related content of "IC chip power supply detection" brought by the core creation detection. Through this article, I hope it can be helpful to you. If you like this article, you might as well continue to pay attention to our website, and we will bring more wonderful content later. If you have any needs related to the inspection and testing of electronic products, please call Chuangxin testing, and we will serve you wholeheartedly.