Maxim Introduces Dual, Quick-PWM™ Step-Down Controller For Notebook Power Supplies

Maxim Integrated Products introduced the MAX17101, a dual, Quick-PWM™ step-down controller with synchronous rectification for generating 5V/3.3V supplies in battery-powered systems. This highly integrated device consists of four output-voltage regulators, allowing it to save space while generating multiple supplies for notebook computers. An internal, 100mA linear regulator can be used to generate either the 5V bias needed for power-up or other lower-power, "always-on" suspend supplies. The controller also includes a low-current (5mA), "always-enabled" linear regulator to power the real-time clock (RTC) when all other notebook regulators are disabled. The MAX17101 is ideal for notebook computers, tablet PCs, and other portable devices.

The device employs low-side MOSFET sensing to provide what is described as low-cost, highly efficient current sensing for valley current-limit protection. Combined with the output overvoltage- and undervoltage-protection features, this current limit is said to ensure robust output supplies. It is claimed that these 5V/3.3V SMPS outputs can save power by operating in pulse-skipping mode, or in ultrasonic mode to avoid audible noise.

Maxim’s proprietary, Quick-PWM architecture enables the MAX17101 to handle fast load steps while maintaining a relatively constant operating frequency and inductor operating point over a wide range of input voltages. This approach is said to circumvent the poor load-transient timing problems of fixed-frequency, current-mode PWM controllers, while also avoiding the problems caused by widely varying switching frequencies in conventional constant-on-time and constant-off-time PWM schemes.

The MAX17101 is available in a 5 x 5mm, 32-pin TQFN package, and is fully specified over the -40 to +85°C extended industrial temperature range. Prices start at $4.00 (1000-up, FOB USA).