RT5035A/B
extend battery operating voltage range. The output
voltage of CH5 is adjustable by the I2C interface in the
range of 1.2V to 2V or set by external feedback
resistors, as expressed in the following equation :
VNEG Charge Pump
The Charge pump is to increase the Vgs driving of big
PMOS in Ch2/3/4/5/10. When BAT < 3.6V and one of
Ch2/3/4/5/10 turns on, VNEG Charge Pump would turn
on and start to pump. But when pumping, the BAT
threshold to turn off and stop charge pump becomes
3.9V. When pumping, the (BAT VNEG) voltage would
be clamped at 4.5V. But because of charge pumping
architecture limitation, most negative level of the VNEG
is only (BAT). Hence, if BAT < 4.5 / 2 = 2.25V, VNEG
is limited to (BAT). When VNEG Charge pump is off,
VNEG is connected internally to GND.
VOUT_CH5 = (1 + R1 / R2) x VFB5
where VFB5 is 0.8V typically and suggested value for
R1 is 100k to 600k.
CH6 : Generic LDO
CH6 is a generic low voltage LDO for multiple purpose
power. The CH6 is a linear regulator, designed to be
stable over the entire operating load range with the use
of external ceramic capacitors. CH6 has an ON/OFF
control which can be set by I2C commands. The output
voltage of CH6 is adjustable by the I2C interface in the
range of 1.2V to 3V.
CH3 : Synchronous Step-Down DC-DC Converter
CH3 is suitable for core power in DSC system. The
converter operates in fixed frequency PWM mode with
integrated MOSFETs, FB resistors and compensation
network. The CH3 step-down converter can be
operated at 100% maximum duty cycle to extend
battery operating voltage range. The output voltage of
CH3 is adjustable by the I2C interface in the range of
1V to 1.3V. Besides, the CH3 also can be adjusted
output voltage if I2C is set to use the external resistor.
The VOUT can be calculated by the equation as below :
CH7 : WLED Driver
CH7 is a WLED driver operates at asynchronous
step-up mode with an internal MOSFET and internal
compensation. The LED current is defined by FB7
voltage and the external resistor between FB7 and
GND. The FB7 regulation voltage can be set in 32
steps from 9.2mV to 300mV, typically, via I2C interface.
The WLED current can be set by the following equation :
ILED (mA) = [0.3V / REXT] x (DIM7 + 1) / 32
VOUT_CH3 = (1 + R1 / R2) x VFB3
Where VFB3 is 0.8V typically and suggested value for
Where REXT is the current sense resistor from FB7 to
GND and (DIM7 + 1) / 32 ratio refers to I2C control
register file. The 0.3V voltage is with ±5% accuracy.
R1 is 100k to 600k.
CH4 : Synchronous Step-Down DC-DC Converter
CH4 is suitable for digital I/O power in DSC system.
The converter operates in fixed frequency PWM mode
with integrated internal MOSFETs, FB resistors and
compensation network. The CH4 step-down converter
can be operated at 100% maximum duty cycle to
extend battery operating voltage range. The output
voltage of CH4 is adjustable by the I2C interface in the
range of 1.35V to 2.14V.
The maximum ILED is defined by 0.3V / REXT
.
CH8 : Generic LDO
CH8 is a generic low voltage LDO for multiple purpose
power. The CH8 is a linear regulator, designed to be
stable over the entire operating load range with the use
of external ceramic capacitors. CH8 has an ON/OFF
control which can be set by I2C commands. The output
voltage of CH8 is adjustable by the I2C interface in the
range of 1.5V to 5.2V.
CH5 : Synchronous Step-Down DC-DC Converter
CH5 is suitable for CMOS sensor power in DSC system.
The converter operates in fixed frequency PWM mode
with integrated internal MOSFETs, FB resistors and
compensation network. The CH5 step-down converter
can be operated at 100% maximum duty cycle to
Copyright © 2020 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5035A/B-03 February 2020
www.richtek.com
21
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