I have a hand held HDMI generator in to repair, and I need a boost/buck con verter IC. I drew out the circuit but can't find an exact match. I'm pret ty sure I need a 5V output as the reg feeds the HDMI DC output.
Since this is battery operated and assuming it should run with weak batteri es, this should maintain a consistent 5V output whether the battery pack (4 X AA) is at 6V or below 5V
The IC is an SOT-23-6 case. Pin 6 is the DC VIN in, pin 5 is the out. Pin 1 is the SW pin (connected to the VIN pin via a 6uh inductor) and pin 2 is ground. The rest I'm not completely sure of, but it looks like pin 3 is the feedback and pin 4 is the enable (it's connected to the VIN by a 1 meg resistor).
The pin 5 feeds the anode of a Schottkey diode, the cathode presumably bein g the DC output as the cathode of this diode feeds a fuse near the HDMI con nectors and there is continuity between that fuse and one of the pins of bo th of the HDMI connectors.
This IC looks a lot like the circuit I drew out:
The problem is that the max voltage allowed for that IC is 6V and four fres h alkalines at 1.6 each would exceed this or certainly push it to the absol ute limit. I can probably add a diode to drop the input by 0.6 but I'd lov e to find the original. Plus, the voltage selection equation would require a change of resistors on the FB pin and I'd have to eliminate the Schottkey diode.
Because the case blistered a bit, the print is hard to read, but it looks l ike VZVAC The Z could be a 7. The only letters I'm fairly sure of is the last three "VAC". In any case, I can't find anything searching on any comb ination of those letters/numbers.
I know it's a long shot but if anyone can point me in the right direction I 'd appreciate it. It's kind of tight in the case but as a last resort I ca n probably stuff a 5V fixed regulator inside.