SN8P1829
8-Bit MCU build-in 12-bit ADC + PGIA + Charge-pump Reg 128 dots LCD driver
SONiX TECHNOLOGY CO., LTD
Page 119
Version 1.0
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Charge-Pump, PGIA and OPA
OVERVIEW
The SN8P1829 has a built-in Voltage Charge-Pump/Regulator (CPR) to support a stable voltage 3.8V from pin
AVDDR with maximum 5mA current driving capacity. This CPR provides stable voltage for internal circuits (PGIA,
ADC and OPA) and external sensor (e.g. blood pressure sensor, thermistor, etc). The SN8P1829 also integrated
12-bit Analog-to-Digital Converters (ADC) up to 2048-step resolution. A very low noise chopper-stabilized
programmable gain instrumentation amplifier (PGIA) with selectable gains stage one of16x, 32x, 64x, 128x and gains
stage two of 1.3x ~ 2.5x.
BLOCK DIAGRAM
Figure 14-1 illustrates a block diagram of the Charge-Pump Regulator, PGIA and OPA module. To obtain maximum
range of ADC output, the ADC maximum input signal voltage should be close to but can’t over AVREFH and the
minimum input signal voltage should be close to but can’t be under the AVREFL, Choosing a suitable reference
voltage and a suitable gain of PGIA can reach this purpose.
Figure 14-1 Block Diagram of Charge-Pump Regulator, PGIA and OPA module
OP 1
OP1IN+
OP1IN+
OP1OUT
OP 2
OP2IN+
OP2IN+
OP2OUT
16/32/64/128
GAIN 2
1.3 ~ 2.5
PGIABIAS
PGIAIN-
PGIA
Charge-Pump Regulator
VDD
3.6V
VDD
CPRENB = 0
CPRENB = 1
AVDDCP
AVDDR
C+
C-
GAIN 1
PGIAOUT