The Texas Instruments LM5155 device is an asynchronous boost controller with a wide input range. It uses peak current mode control to achieve boost, SEPIC and flyback topologies. If the bias pin is connected to the V (CC) pin, the LM5155 can be started from a single battery with a minimum of 2.97V. When the bias pin is greater than 3.5V, the input voltage can be as low as 1.5V.
The internal V (CC) regulator also supports offset needle operation up to 45 V (50 V absolute maximum). The switching frequency can be dynamically programmed via an external resistor from 100kHz to 2.2MHz. Switching under 2.2MHz can minimize AM band interference, and allow smaller solution size and fast transient response. The device has a 1.5A standard MOSFET driver and a low 100mV current limiting threshold. The device supports the use of external V (CC) power to improve efficiency. Low operating current and wave hopping operation improve the efficiency under light load.
The device has built-in protection functions such as circulating current limiting, overvoltage protection, line UVLO and thermal shutdown. Hiccup mode overload protection is available in the LM51551 device option. The controller includes low shutdown I (Q), programmable soft start, programmable ramp compensation, precise reference, PGOOD indicator and external clock synchronization.
