Rev. 1.10
146
November 04, 2019
Rev. 1.10
147
November 04, 2019
HT45F5Q-3
Battery Charger Flash MCU
HT45F5Q-3
Battery Charger Flash MCU
Constant Voltage Mode Description
Constant voltage charging means that the charge voltage will remain at a constant value no matter
how the battery internal resistance changes. The principle is that the charge voltage B+ is divided by
R3 and R4 resistors and then supplied to the OPA1 negative terminal through the OPA1N pin. The
difference between the OPA1N voltage and the D/A converter voltage is amplified and then output
on the OPAE pin. This output will be sent to the PWM IC via a photo-coupler. If the OPA1N voltage
is lower than the DAC1 voltage, the PWM IC will increase the PWM duty cycle and vice versa.
Note: The DA1H and DA1L registers are used to set the maximum voltage threshold.
Improving the Constant Current and Constant Voltage Resolution
If the internal 14/12-bit D/A Converter resolution is not high enough, the OPA0 and OPA1 positive
terminals can be supplied by an external divider resistor to increase the voltage and current
resolution.
Hardware Circuit
5V
5V
L
N
AC 1
IC1
PC817
5V
Q3
TRx
Vout
BAT
OPAE
Vout
Charger Temperature
Battery Temperature
RLED
GLED
D2
D1
D3
D5
C4
C5
R12
C7
C13
D6
D7
R13
C10
C8
D4
R15
R16
R17
R18
R20
R24
D8
D9
D10
C15
C18
C22
C23
C17
C14
C9
C11
R10
R5
R6
R9
R22
R23
R25
R26
C19
C20
C21
C12
R11
R1
R2
R3
R4
R8
R7
R14
C1
C2
C3
C6
F1
NTC1
VDR1
C16
Vin
Vout
GND
U2
HT7550-2
Q2
R19
B+
B-
R21
R27
B+
B-
B-
B-
CMP
1
VFB
2
CS
3
RC
4
VREF
8
VCC
7
OUT
6
GND
5
IC2
3844
Q1
VSS
1
VDD
2
3
4
PB0/AN0
5
6
7
8
PA1/OPA2P
9
PA0/ICPDA
10
PA2/ICPCK
11
PA3/CTP/CTCK/INT0/SDO/TX
12
PA4/STP/STCK/SDI/SDA/RX
13
PA7/SDO/TX
14
PC2/SDI/SDA/RX
15
PC1/AN9/SCK/SCL
16
PC0/AN8/SCS
17
PB7/AN7
18
PB6/AN6/INT1
19
PB5/AN5
20
12Bit
10K
DAC
OPA1P
OPA0P
14Bit
10K
DAC
OPA1N
OPA0N
PB4/AN4
21
PB3/AN3
22
PB2/AN2/STPI
23
PB1/AN1/VREF
24
U?
HT45F5Q-3
Charger Application Circuit