Q
We are designing a digital camera with ADP5046. The PMU device is powering up
and immediately shutting down all outputs. We are not using the external
crystal. Do you have an idea how to bring up the supplies? We can communicate
via I2C and alter the registers but nothing seems to work.
A
Refer to the datasheet table 74 on page 56 (copied below). Address 100, bit 0
sets whether channel 8 is in sequencer mode or I2C mode.
In this case, for the 0008 version, the default setting is sequencer mode.
That means that when EN goes high, channel 8 will startup according to the
preset EN delay time and SS time.
In your case, the Channel 8 input is not connected. So when CH.8 tries to
start, there is no output voltage.
The ADP5046 detects this as an under-voltage condition and shuts down.
To confirm that this is the problem, I suggest the following:
Before setting EN high, program address 100, bit0 to I2C mode. You will have to
have I2C powered up and battery voltage applied.
I2C mode means that the sequencer is not applied to the channel, rather the
channel is disabled by default and can be enabled via I2C.
Another option would be to disable the UV delay protection. This is address 101
and can be set to UV disable.
If this solves the problem, then I recommend that you connect VBATT to channel
8 input. This should startup normally with no I2C modifications required.
There is a version of the part (0012) which has Channel 8 set to I2C mode by
default.
