RT5028B
Operation
The RT5028B is a highly-integrated solution for industrial
system including 4-CH step-downDC-DC converters and
8-CH LDOs. The RT5028B application mechanism will be
introduced in later sections.
Over-Temperature Protection
An Over-Temperature Protection (OTP) is contained in the
device. The protection is triggered to force the device
shutdown for protecting itself when the junction
temperature exceeds 165°C typically. Once the junction
temperature drops below the hysteresis 10°C typically,
the device must be re-send PWRON to start system.
The power-on and power-off sequences can be controlled
by I2C or each EN pin and detected in MASK_GPIO pin.
When the MASK_GPIO pin is at Hi level, the PMIC follows
the power-on sequence to turn on channels. When the
MASK_GPIO pin is at Lo level, the channels of PMIC will
be controlled by the EN pin.
Output Under-Voltage Protection
The output under-voltage protection is implemented in order
to prevent operation at low output voltage conditions.
When the step-downDC-DC converters output voltage is
lower than 1/2 x (VOUT), the UVP event triggers and PMIC
turns off immediately.
Synchronous Step-Down DC-DC Converter
Four current mode synchronous step-down DC-DC
converters operate with internal power MOSFETs, FB
resistors and compensation network. These channels are
suitable for core power in industrial system. They can be
operated at 100% maximum duty cycle to extend battery
operating voltage range. When the input voltage is close
to the output voltage, the converter enters low dropout
mode with low output ripple. The operating frequency of
step-down converter is adjustable from 500kHz to 2MHz
and is controlled by I2C. Besides, the I2C interface also
can be used to select different operation modes, On/Off
Sequence, programmable the output voltage, RAMP
control and discharge function. To enableAUTO Mode, it
is used to improve the efficiency at light load. If theAUTO
Mode is disabled, the converter operates in force PWM
mode with fixed switching frequency.
Linear Regulator
Eight generic low voltage LDOs for multiple purpose power.
The LDOs are stable over the entire operating load range
with the use of external ceramic capacitors. The LDOs
also have I2C programmable power on/off sequence and
discharge function. The output voltage is adjustable by
the I2C interface in the range of 1.6V to 3.6V.
Copyright 2016 Richtek Technology Corporation. All rights reserved.
©
is a registered trademark of Richtek Technology Corporation.
DS5028B-01 September 2016
www.richtek.com
5
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
