SG1845

The SG1844/45 family of control ICs provides all the necessary features to implement off-line fixed frequency, current-mode switching power supplies with a minimum number of external components. Current-mode architecture demonstrates improved line regulation, improved load regulation, pulse-bypulse current limiting and inherent protection of the power supply output switch.

The bandgap reference is trimmed to ±1% over temperature. Oscillator discharge current is trimmed to less than ±10%. The SG1844/45 has undervoltage and start-up current of less than 1mA.

The totem-pole output is optimized to drive the gate of a power MOSFET. The output is low in the off state to provide direct interface to an N-channel device.

Both operate up to a maximum duty cycle range of zero to <50% due to an internal toggle flip-flop which blanks the
output off every other clock cycle.

The SG1844/45 is specified for operation over the full military ambient temperature range of -55 to 125.

The SG2844/45 is specified for the industrial range of -25 to 85, and the SG3844/45 is designed for the commercial range of 0 to 70.