Baker clamp

Baker clamp is a generic name for a class of electronic circuits that reduce the storage time of a switching bipolar junction transistor (BJT) by applying a nonlinear negative feedback through various kinds of diodes.

The diode-based Baker clamps prevent the transistor from saturating and thereby accumulating a lot of stored charge.

[8] Shea's 1957 text does describe the clamp circuit and references Baker's technical report.

When the transistor is cutoff, the output is similar to an RC circuit that exponentially decays to its final value.

As the circuit gets closer to its final value, there is less current available to charge the capacitor, so the rate of approach lessens.

[11] Cutoff clamping reduces the output voltage swing but makes the transition faster.

While the transistor is in active mode and it is far away enough from the saturation point, the negative feedback is turned off and the gain is maximal; when the transistor approaches the saturation point, the negative feedback gradually turns on, and the gain quickly drops.

[15] A simple alternative to the Baker clamp is a single low-voltage diode from the collector to the base.

[17] One drawback of the Baker clamp is its increased low voltage-output level (as in a Darlington transistor).