Circuit for generating from low voltage edges higher voltage pulses having precise amplitudes and durations

摘要

A low voltage source of input edges for a pulse of precision duration is applied to an input buffer to provide a low impedance source whose output is AC coupled to positive and negative edge differentiators. Each differentiator briefly drives ON a corresponding normally OFF switch, the pair of which switches serves as an impulse driver and that may be clamped to symmetrical opposing reference voltages. The clamped impulse driver may also be coupled to a bi-stable switch driver that responds to a particular polarity impulse driver voltage by applying thereto through a load resistor a percentage of a power supply voltage of opposite polarity. The bi-stable switch driver changes state each time input edges of alternating polarity are applied to the input buffer. The impulse driver is also coupled to the gates of a complementary pair of MOSFET switches that are in series between precise reference voltages of opposing polarities, and whose common junction may be connected to a current determining resistance whose other end is connected to a using circuit, such as an integrator. The output of the MOSFET switches may be assisted by an auxiliary bi-stable output driver that reduces the amount of load current drawn from those MOSFETs, and thereby reduces errors arising from thermally induced variations in their on resistance.