M51994P

The M51994P is a semiconductor integrated circuit designed for controlling  primary-control  two-output switching regulators and it is best suitable for obtaining DC stabilized voltage from the commercial power supply.This  provides fast rise/fall  time of the output voltage as well as output current,allowing the direct driving of the MOSFET.This also provides fast rise/fall time on output pulses and it equips a high-speed and highly-sensitive current limit circuit therefore, you can create really high-speed switching regulators using the device.Since it contains a timer type protection circuit, the protection in case of any  excess output current (i.e. due to a short-circuit) can be done easily only by adding few parts to the primary side.

Features of the M51994P are:(1)output current:12 A;(2)output rise time=60ns, Output fall time=40ns;(3)small pre-operation current:110A (standard);(4)uses a pulse-by-pulse  current limiting method (CLM-pin)which minimizes required peripheral circuits;(5)supports the protection for excess output current:timer-type protection circuit;(6)uses a deforming totempole output method which require small through current;(7)supports 2-output drive functions using a steering circuit.(applicable  for  push-pull,  half-bridge,  and  full-bridge circuits);(8)supports the OVP function which keeps the power OFF status once a signal is input.

The absolute maximum ratings of the M51994P can be summarized as:(1)supply voltage:31V;(2)collector pin applied voltage:31V;(3)OVP-pin applied voltage:Vcc V;(4)operation temperature:-30 to +85°C;(5)storage temperature:-40 to +125°C.When  the  current  limit circuit  is activated  and  the  VF voltage  becomes below  some  level,  the dead  time is extended  and  the  intermittent  action  circuit(timer  type protection circuit) starts working. The intermittent action and  oscillation  control  circuit  generates signals for  controlling  oscillators  and  intermittent action  circuits  using current limit signals.Noise  voltage  may  be  generated  at  Rclm  when  the transistor  is set to ON due to the snubber circuit or the capacity  between  coils of  a  transformer.  The  CLM may malfunctions because of this noise voltage so that noise-cut filters RNF and CNF are connected in the figure.