MP161 – INTEGRATED POWER SOLUTION FOR HOME/INDUSTRIAL AUTOMATION
VIN
Standby Mode Operation
The MP161 can switch between normal
operation mode and standby mode according to
OUTx
the input on STBY. When STBY is low, the
MP161 works in normal mode, and the output
voltage of the switching regulator is regulated
based on VCCREF (fixed output) or VREF
INx
GND
(adjustable output). When STBY is high, the
chip works in standby mode, and the switching
Figure 4: Block Diagram of Internal Relay Driver
OVP on VIN
regulator output is regulated at VCCSTBY
.
Standby mode is used to save power by
reducing the switching regulator output voltage
when the load on this output rail is idle.
A propriety OVP feature is implemented in the
MP161. When the voltage on VIN exceeds VOVP
the switching regulator is shut down to stop
energy from flowing to the output any further.
There is also an internal current pulled from VIN
to help discharge the external capacitor when
OVP is triggered. This protection feature can
prevent damage on critical loads from over-
stress when VIN regulation fails.
,
When entering standby mode, the VCC
regulating voltage drops step-by-step to keep
the output properly regulated. There is also a
soft-start procedure when exiting standby mode.
MP161 Rev. 1.0
8/4/2017
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