The LTC4020 is a high voltage power manager providing PowerPath™ instant-on operation and high efficiency battery charging over a wide voltage range. An onboard buck-boost DC/DC controller operates with battery and/or system voltages above, below, or equal to the input voltage. The LTC4020 seamlessly manages power distribution between battery and converter outputs in response to load variations, battery charge requirements and input power supply limitations. The LTC4020 battery charger can provide a constant-current/constant-voltage charge algorithm (CC/CV), constant-current charging (CC), or charging with an optimized 4-step, 3-stage lead-acid battery charge profile. Maximum converter and battery charge currents are resistor programmable. The IC's instant-on operation ensures system load power even with a fully discharged battery. Additional safety features include preconditioning for heavily discharged batteries and an integrated timer for termination and protection.