Replace backup battery regulator

[bschulz1701]

Issue:

Current backup battery charger (voltage regulator) TCR2LE31 has an output discharge feature which can cause the backup battery to be discharged when the system stops charging it.

Potential Solution:

Choose an alternate converter without output discharge

[bschulz1701]

Regulator requirements:

• Low I_Q (<2μA)
• Low dropout voltage (<400mV)
• Small form factor to prevent board reorganization (SC-70 or smaller)
• No output discharge

Potential option: TPS7A0331

[bschulz1701]

If a regulator without output discharge is used, D19 can be removed