HT45F4N Datasheet, PDF (118/170 Pages) Holtek Semiconductor Inc – Power Bank Flash MCU

HT45F4N/HT45FH4N
Power Bank Flash MCU
Over Current Protection
The device includes an over current protection function which provides a protection mechanism for
the battery charge and discharge applications.
OCP Funciton
To prevent the possibility of large battery current and load current, the OCP input voltage from the
battery sense resistor is compared with a reference voltage generated by an 8-bit D/A converter. The
8-bit D/A converter power is supplied by the external power pin named DAPWR. Once the OCP
input voltage is greater than the reference voltage, it will force the OUT0H/OUT1H and OUT0L/
OUT1L signals inactive, i.e., the OUT0H/OUT1H signal will be forced into a high state and the
OUT0L/OUT1L signal will be forced into a low state before the polarity control, to turn the external
MOS off for over current protection.
The OUT0H/OUT1H and OUT0L/OUT1L signals can be forced to an inactive state when an over
current event occurs. If an over current event occurs, the corresponding interrupt will be generated.
Once the over current condition has disappeared, the OUT0H/OUT1H and OUT0L/OUT1L signals
will recover to drive the PWM output.
The operational amplifier in the over current protection circuitry can be configured in an inverting or
non-inverting OPA configuration to sense the battery current when the battery is undergoing a charge
or discharge operation. It is recommended that the OPA should be in a non-inverting mode during a
charge operation and in an inverting mode during a discharge operation.
More information for the OUTnH and OUTnL signal polarity and output control is described in the
TMPCn register.
OCP Circuit Operation
OCP is abbreviation of over current protects circuit. OCP detect input voltage which is proportional
to the monitored source current; if the input voltage is larger than reference voltage set by DAC,
OCP will issue an output signal indicate the source current is over specification.
OCPnM1� OCPnM0
OCPnDA
fFLT=fH/�
OCP Input
S0
S1
S�
S3
8 �it DAC
G=1/5/10/15/�0
C
A
R1
R�
(R1=�0K)
Filte� �lo�k
Filte�
OCP0O
To ADC
OCPnG�~OCPnG0
OCPnF�~OCPnF0
Over Current Protection Block Diagram (n=0 or 1)
Rev. 1.30
118
December 14, 2016