LM9061

The LM9061 family consists of charge-pump devices which provides the gate drive to an external power MOSFET of any size configured as a high-side driver or switch. This includes multiple parallel connected MOSFETs for very high current applications. A CMOS logic-compatible ON and OFF input controls the output gate drive voltage. In the ON state, the charge pump voltage, which is well above the available V_CC supply, is directly applied to the gate of the MOSFET. A built-in 15-V Zener clamps the maximum gate to source voltage of the MOSFET. When commanded OFF a 110-µA current sink discharges the gate capacitances of the MOSFET for a gradual turnoff characteristic to minimize the duration of inductive load transient voltages and further protect the power MOSFET.

Lossless protection of the power MOSFET is a key feature of the LM9061. The voltage drop (V_DS) across the power device is continually monitored and compared against an externally programmable threshold voltage. A small current-sensing resistor in series with the load, which causes a loss of available energy, is not required for the protection circuitry. If the V_DS voltage, due to excessive load current, exceeds the threshold voltage, the output is latched OFF in a more gradual fashion (through a 10-µA output current sink) after a programmable delay time interval.