2.5V to 22V Input, 7.8A Switching Current High-Efficiency Buck-Boost Converter for USB-PD/PPS Applications

The MAX77859 is a high-efficiency, high-performance buck-boost converter targeted for systems requiring a wide input voltage range (2.5V to 22V). The IC can supply up to 6A of output current in buck mode and up to 4A in boost mode (VIN = 3.7V, VOUT = 5V). The IC allows systems to change the output voltage dynamically through I2C serial interface.MAX77859A features I2C-adjustable output current limit with resolutions of 50mA/step (with 10mΩ sense resistance) to support USB-C PPS requirements. MAX77859B is a non-PPS version and is optimized for low quiescent current. Systems equipped with MAX77859 can provide fast-charging peripheral devices with higher output voltage, minimizing power loss across cable/connector and reducing charging time.

The IC operates either in SKIP mode or in forced-PWM (FPWM) mode, depending on the operating conditions, to optimize efficiency. The default output voltage is 5V when using internal feedback resistors. The IC can also be configured to any default output voltages between 3V and 20V when using external feedback resistors. The output voltage is adjustable dynamically (DVS) between 3.2V and 16V in 20mV steps when using internal feedback resistors or between 3V to 20V when using external feedback resistors (with step-size dependent on the external feedback resistor ratio) by programming the internal reference voltage through I2C serial interface. See the Output Voltage Configuration section for more information.

MAX77859A features output current limit. Using a 10mΩ sense resistor, the output current limit threshold is adjustable dynamically between 1A and 5A in 50mA steps through I2C serial interface, with a 3A default value.

The SEL pin allows a single external resistor, RSEL, to connect to AGND to program the following:

* I2C Interface Target Address (4 options)

* Switching Current Limit Threshold (4 options)

* Feedback Resistor Selection (Internal or external)

APPLICATIONS

* USB PD 3.0 (PPS) Dynamically-Reconfigurable Processor (DRP) Applications

* Space-Constrained Applications

* Wide Input Voltage Range: 2.5V to 22V

* Programmable Output Voltage

* 3.2V to 16V with Internal Feedback Resistors

* 3.0V to 20V with External Feedback Resistors, See Table 1

* USB Type-C® Power Delivery (PD)/Programmable Power Supply (PPS)

* 20mV Output Voltage Step Size

* 50mA Output Current Limit Step Size

* Maximum Output Current

* Buck Mode: Up to 6A

* Boost Mode: Up to 4A (VIN = 3.7V, VOUT = 5V)

* 7.8A Typical Switching Current

* Automatic SKIP Mode and Forced-PWM Mode

* RSEL Configuration

* I2C Interface Target Address

* Switching Current Limit Threshold

* Internal/External Feedback Resistors