The LM5156x device is a wide input range, non-synchronous boost controller that uses peak-current-mode control. The device can be used in boost, SEPIC, and flyback topologies.
The 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 60 V (65-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. To reduce the EMI of the power supply, the device provides an optional dual random spread spectrum, which reduces the EMI over the wide frequency span.
The device features a 1.5-A standard MOSFET driver and a low 100-mV current limit threshold. The device also 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 LM51561 device option. Additional features include low shutdown IQ, programmable soft start, programmable slope compensation, precision reference, power good indicator, and external clock synchronization.