MIC9131 Micrel, Inc. MIC9131
High-Voltage, High-Speed Telecom
DC-to-DC Controller General Description Features The MIC9131 is a current-mode PWM controller that efficiently
converts –48V telecom voltages to logic levels. The MIC9131
features a high voltage start-up circuit that allows the device to
be connected to input voltages as high as 180V. The high input
voltage capability protects the MIC9131 from line transients
that are common in telecom systems. The start-up circuitry
also saves valuable board space and simplifies designs by
integrating several external components.
The MIC9131 is capable of high speed operation. Typically
the MIC9131 can control a sub-25ns pulse width on the gate
out pin. Its internal oscillator can operate over 2.5MHz, with
even higher frequencies available through synchronisation.
The high speed operation of the MIC9131 is made safe by
the very fast, 34ns response from current sense to output,
minimizing power dissipation in a fault condition.
The MIC9131 allows for the designs of high efficiency power
supplies. It can achieve efficiencies over 90% at high output
currents. Its low 1.3mA quiescent current allows high efficiency
even at light loads.
The MIC9131 has a maximum duty cycle of 75%. For designs
requiring a maximum duty cycle of 50%, refer to the MIC9130. …