Because of the epidemic, I received it after the Spring Festival, and then I found that the voltage could not be measured on the CH241K evaluation board (I suspected that the coil was broken). Thanks to eeworld for sending me another set of evaluation boards. Unfortunately, I went on a business trip immediately after receiving it and have not returned yet. I have said so many excuses, but it cannot cover up the fact of procrastination.
Fortunately, I took some photos on my phone, so I’ll post them here:
1. How to use the board
The CH246D board is a wireless power supply terminal. After connecting to Type-C, it can provide external power through the antenna.
Note that there is an isolation magnetic pad on the back of the coil. When installed close to the outer shell, it can prevent interference to the internal circuit. After testing, even if the isolation magnetic pad is cracked, it still has a good isolation effect.
The CH241K board is the power receiving end, which obtains energy from the coil. According to the introduction, it supports a maximum output of 5W.
Turn on the power and try driving a fan.
At this time, the power consumption of the entire system is about 4.6W.
When not loaded, the power consumption varies greatly (the reading on the meter is 0.11w~0.23w), and basically does not exceed 0.3w
The voltage and current applied to the fan have not been tested, so the system efficiency test has not been completed.
2. What is the compatibility of the chip?
I found a Baseus mobile phone wireless charger
And a portable mobile phone charger
Used to verify the wireless charging and power receiving performance of CH241.
First, use the CH246D board as the source and output a voltage of 5.03V from the CH241K without load.
Using a wireless charger as a source, the no-load output voltage on the CH241K is 5.03V
Using a power bank as the source, the no-load output voltage on CH241K is 5.03V
The test leads may have been connected in reverse during the above test, but this does not affect the test conclusion: the compatibility of CH241K seems good, and the output voltage is relatively stable.
3. Is the output voltage still stable after connecting the load?
Still using a small fan as a load test, the output voltage dropped by 0.01V.
It can be considered that when placed in close contact, the output voltage of CH241 is relatively stable.
4. Effective distance of CH241&CH246 energy transmission
Slightly lift the coil of CH241K by hand and observe the multimeter display at the same time. You will find that there is an intermediate process from 5.03V to 0V, as follows:
The output voltage is slightly lower than 5V, but there is still output. If the coil is slightly raised, there is no voltage output. At this time, the distance between the two coils is about 5~8mm.
5. Can a medium be placed between the coils?
In the previous test, the coil was lifted manually, which can be regarded as placing an air medium between the two coils, verifying that wireless energy transmission can still be achieved under the air medium.
If a coil is turned over, energy transmission cannot be achieved, indicating that the energy transfer of the coil is isolated by the ferromagnetic material. To verify this idea, I disassembled the magnetic suction of a wallet.
The diameter of this magnet is about 15mm and the thickness is about 2mm. It is placed between the two coils.
It can be seen that the output voltage drops significantly.
Use an anti-static bag and place it between the two coils to not affect the output voltage
Try changing other media.
Wood medium (thickness about 5mm), output voltage 5.03V
Organic glass medium (thickness about 5mm), output voltage 5.03V
N95 mask (with packaging, thickness about 2mm), output voltage 5.03V
Energy transmission between coils can be achieved through a common medium in daily life, but the distance between the two coils cannot be too far.
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