BQ25070: Iout is always 990mA

Hi Nick,

I think I couldn't explained my question clearly.

When we set 5 pulses of CTRL, so the theoretical input current is 187mA. According to your answer, the output current should be the same as the input current 187mA. However we measured output is 3.7V/990mA.
Actually no matter how many pulses are set to the CTRL Iout is always 990mA.
We don't know the reason so posted here.

Beat Regards,
Tom Liu

Hi Tom,

Without any pulses the default Ilim should be 285mA. Is this observed?

Please upload the schematic and if possible the waveform of the control signal. Also did you measure the input current? 

Thanks, 

Hi Nick,

I will ask the customer to provide schematic and waveform. He said the input current is difficult to measure before.

Figure 10 of the data manual describes the relationship between the charge current and the input voltage. Can this be the reason? Since the input is 5V, the charge current is 990mA, no matter how large the input current limit is. In addition, the meaning of red and blue is not given in the figure.

Beat Regards,
Tom Liu

Hi Tom,

Figure 10 is meant to show the thermal regulation behavior of the device, for the blue curve Ilim is set to 935mA (11 pulse). It is not meant to be interpreted as a general input voltage vs output current curve.

Best,

Hi Nick,

I updated the schematic and the waveform.
Could you give us some advice?

Beat Regards,
Tom Liu

Hi Tom,

1. When the TS pin is not used it cannot be left floating, see figure 14 of d/s for instruction
2. 0.1 uF cap on LDO is required
3. The pulses must be no longer than 1ms high and 1ms low, in the waveform the pulses look to be around 50ms

Best,