TPS61222: The output of the rectifier circuit is 2.22V, but the current is only 2-3mA. The cascade boost chip cannot work normally. Is it because of the current?

Dear User:

1. The manual of TPS61222 states that the ISW switch current is limited to 200mA. Does it mean that 200mA is required to make the chip work properly? The results of my tests seem to require that the input current be greater than 200mA.

No, it's the peak-peak current of the inductance. The average current is smaller than half if in DCM with so light load. But during the startup, the circuit need to charge the output capacitance. It needs enough current to charge it. It could be hundreds mA depends on the components.

2. Does the quiescent current in the data sheet refer to the current value during normal operation after turning on the MOS transistor?

The quiescent current is testes without switching. Here is an application note clarify it clearly. http://www.ti.com/lit/an/slyt412/slyt412.pdf?keyMatch=WHAT%20THE%20IQ&tisearch=Search-EN-technicaldocument

3. What does the output ILKG_VOUT leakage current 1uA mean?

The spec is tested with "VEN = 0 V, VIN = 1.2 V, VOUT = 3.3 V". Measure the current flow into the VOUT pin. 

4. The output of the rectifier circuit is 2.22V, but the current is only 2-3mA. The cascade boost chip cannot work normally. Is it because of the current?

What's your power supply now? Could you test with enough input current capability supply? If the issue is still exist, please catch the waveform of the Vin, Vout, SW, and Icoil.
5. Can you recommend some boost chips that require a small input current, thank you.

May you share more details information about your application and requirements? So that I can give better suggestion. 

thanks for your reply.

Because the voltage received through electromagnetic induction is relatively small, a rectifier circuit is used.
After rectification, the output voltage is between 1-2V and the current is only 2-3mA. I want to use a charging chip with a power voltage of 5V to charge the lithium battery, so I want to add a boost module in the middle.
Because the output current of the rectifier module is relatively small, the TPS61222 cannot work normally
So I hope you recommend a boost chip with an input current of 2-3mA, which can increase the voltage from 1-2V to 5V

best wishes

Dear user:

You could add a supercap to smooth the current ripple. It's hard to find a part with peak current smaller than 10mA during the startup. It will be much easier if there is another routing to supply the startup current. 

What's your application used for?

I'm so sorry

I have a new question.

ccording to the parameters of the data sheet, the corresponding 0603 package capacitor and coilcraft power inductor are selected, and the output can reach 5V, but once the load is added, the voltage will become lower. What is the reason for this?

Dear User:

May you share more detail information about the issue? What's the load condition and the Vin capability?

May you catch the waveform of the Vin, Vout, and SW?

hi
I have a question
BQ24002 data sheet indicates that VCC current is 1mA
60mA when output current is precharged
But when I use the actual circuit, I find that the output current is related to the input current. When the output current is 60mA, the input current must also be maintained at 60mA. What is the reason for this?
Can you recommend some current charging chips

Thank you
best wishes