The CS5112 is a dual output power supply integrated circuit. It contains a 5.0 V +/-2%, 100mA linear regulator, a watchdog timer, a linear output voltage monitor to provide a Power On Reset (POR) and a 1.4A current mode PWM switching regulator.
The 5.0 V linear regulator is comprised of an error amplifier, reference, and supervisory functions. It has low internal sup-ply current consumption and provides 1.2 V (typical) dropout voltage at maximum load current.
The watchdog timer circuitry monitors an input signal (WDI) from the micro-processor. It responds to the falling edge of this watchdog signal. If a correct watchdog signal is not received within the externally programmable time, a reset signal is issued.
The externally programmable active reset circuit operates correctly for an out-put voltage (VLIN ) as low as 1.0 V. During power up, or if the output voltage shifts below the regulation limit, RESETbar toggles low and remains low for the duration of the delay after proper output voltage regulation is restored. Additionally a reset pulse is issued if the correct watchdog is not received within the programmed time. Reset pulses continue until the correct watchdog signal is received. The reset pulse width and frequency, as well as the Power On Reset delay, are set by one external RC network.
The current mode PWM switching regulator is comprised of an error amplifier with selectable feedback inputs, a current sense amplifier, an adjustable oscillator, and a 1.4 A output power switch with anti-saturation control. The switching regulator can be configured in a variety of topologies.
The CS5112 is load dump capable and has protection circuitry which includes current limit on the linear and switcher outputs, and an overtemperature limiter.