CH224 Preliminary Function Test

dcexpert

CH224 Preliminary Function Test [Copy link]

 

I have been planning to make a multifunctional portable USB power supply that can be controlled by USB, WiFi, Bluetooth and MicroPython (in fact, the first version of the prototype has been completed and the functions have been tested), which is convenient for daily development, DIY and testing. However, the output power of ordinary USB is relatively small, which limits the scope of application. I plan to use the PD function of USB, but I am not familiar with this part. Some common chips are complicated to use and there are not many functions I need to use. I happened to see that there was an activity of CH224 on the forum, which just suited my needs. I received the development board a few days ago, but I have been working overtime and have no time to test it. I took advantage of the weekend to test the function first.

CH224 supports two ways to configure the output voltage, resistance and level. Forum friend Buyixin has already written a test post , using MCU IO control, so there is no need to repeat this part. After searching for a long time at the bottom of the box, I finally found a 100K potentiometer.

Use alligator clips to connect the potentiometer to the CH224 development board.

Then connect the multimeter to display the voltage, and then connect the fast charging head to test.

The voltage can be easily changed by adjusting the potentiometer, but the lowest output is only 9V, not 5V. However, 5V can be output when the level is configured.

When adjusting the potentiometer, the resistance value does not need to be too precise, and the voltage can be changed within a range. It is estimated that the chip is controlled by a comparator inside.

The default output of 20V is indeed a potential safety hazard. If a CFG error is caused by a cold solder joint, collision, or other unexpected reasons, the voltage will exceed expectations and damage other chips. I hope that some improvements can be made in subsequent versions. In addition, it would be better if the resistor configuration can output 5V.

dcexpert

The charging head needs to support the PD function. Although some mobile phone charging heads also support fast charging, they are not compatible. At this time, the voltage cannot be controlled and the output is 5V.

This charger does not support CH224

This can

dcexpert

CH224 also supports mobile power with PD, such as this model

le062

Using a PD charger as an adjustable voltage source is a good idea

If CH224 is equipped with a DCDC of 20V or above (I just searched it, such as ETA2823, ETA2847), it can be made into a digital adjustable power supply.

To put it simply, use several IOs that support high-impedance and open-drain modes to make an impedance network (already practiced); to put it more complicated, study ADC-DAC feedback or something (imaginary, not practiced).

soso

Looking forward to the work~~