Q: TPS61200 Vout prebias above programmed value by 282017

I have a customer that would like to use the TPS61200 as a backup supply with the input from a supercap.  The output will be set to regulate at 3.6V, but another supply could cause 4V to appear on the output of the TPS61200.

Will the TPS61200 simply stop switching in this case?  Will it pass any current from Vout to Vin?  If it overcharged the supercap due to this reverse leakage that would be bad.


A: Re: TPS61200 Vout prebias above programmed value by 1090425

The IC should be operated in power save mode or disabled in this case.

Based on my testing of the EVM with 1.5V in,

If disabled, the IC will consume about 1 uA into Vout.  With no input source connected, this will raise Vin to about 0.4V.  With a 1.5V input source, the IC will draw about 1uA from Vout and 1.3uA from Vin.  Since current is flowing from Vin, no current will flow onto your supercap.

With the IC enabled in power save mode with an input source connected, it draws 60 uA from Vout and Vin sources 2uA.  Again, no current flows backwards.  With the input floating, it still consumes 60uA from Vout and Vin is raised to about 0.4V