> Now my case using the capacitor-divider to generate a 9mA current
> for payload
>
> This circuit can work fine, but the C1(0.47uF,630V) is too big to us

If it helps, 0.47uF is bigger than necessary. As 1uF passes about 69mA
at 50Hz, 0.15uF would be more like it. 0.47uF would pass 31mA

I = 6fCV

I = 6 * 50 * 0.15 * 10-6 * 220 = 9.9mA

Capacitor should be, and will be marked, X2

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