By Texas Instruments 18
Texas Instruments' LM5155 device is a wide input range, non-synchronous boost controller that uses peak current mode control and can be used in boost, SEPIC, and flyback topologies.
The LM5155 device can start up from a 1-cell battery with a minimum of 2.97 V if the BIAS pin is connected to the VCC pin. It can operate with the input supply voltage as low as 1.5 V if the BIAS pin is greater than 3.5 V.
The internal VCC regulator also supports BIAS pin operation up to 45 V (50 V absolute maximum). The switching frequency is dynamically programmable with an external resistor from 100 kHz to 2.2 MHz. Switching at 2.2 MHz minimizes AM band interference and allows for a small solution size and fast transient response.
The device features a 1.5 A standard MOSFET driver and a low 100 mV current limit threshold. The device supports the use of an external VCC supply to improve efficiency. Low operating current and pulse-skipping operation improve efficiency at light loads.
The device has built-in protection features such as cycle-by-cycle current limit, overvoltage protection, line UVLO, and thermal shutdown. Hiccup-mode overload protection is available in the LM51551 device option. The controller includes low shutdown IQ, programmable soft-start, programmable slope compensation, precision reference, a PGOOD indicator, and external clock synchronization.