XRP7704 Datasheet, PDF (16/31 Pages) Exar Corporation – Quad-Output Digital PWM Buck Controller

REV 1.1.0
XRP7704
Quad-Output Digital PWM Buck Controller
Standby Low Drop-out Regulator
This 100mA low drop-out regulator can be programmed as 3.3V or 5V in SET_STBLDO_EN_CONFIG register.
Its output is seen on the LDOOUT Pin. This LDO is fully controllable via the Enable Pin (configured to turn on as
soon as power is applied), a GPIO, and/or I²C communication.
Enabling, Disabling and Reset
The XRP7704 is enabled via raising the ENABLE Pin high. The chip can then be disabled by lowering the same
ENABLE Pin. There is also the capability for resetting the Chip via an I²C SOFTRESET Command.
For enabling a specific channel, there are several ways that this can be achieved. The chip can be configured to
enable a channel at start-up as the default configuration residing in the non-volatile configuration memory of the
IC. The channels can also be enabled using GPIO pins and/or an I²C Bus serial command. The registers that
control the channel enable functions are the SET_EN_CONFIG and SET_CH_EN_I2C.
Internal Gate Drivers
The XRP7704 integrates Internal Gate Drivers for all 4 PWM channels. These drivers are optimized to drive both
high-side and low side N-MOSFETs for synchronous operation. Both high side and low side drivers have the
capability of driving 1 nF load with 30 ns rise and fall time. The drivers have built-in non-overlapping circuitry to
prevent simultaneous conduction of the two MOSFETs.
Fault Handling
While the chip is operating there are four different types of fault handling:
• Under Voltage Lockout (UVLO) monitors the input voltage to the chip, and the chip will shutdown all
channels if the voltage drops to critical levels.
• Over Temperature Protection (OTP) monitors the temperature of the chip, and the chip will shutdown all
channels if the temperature rises to critical levels.
• Over Voltage Protection (OVP) monitors the voltage of channel and will shutdown the channel if it
surpasses its voltage threshold.
• Over Current Protection (OCP) monitors the current of a channel, and will shutdown the channel if it
surpasses its current threshold. The channel will be automatically restarted after a 200ms delay.
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