Half-Bridge Gate Drive Sensing for Cross-Conduction Control

The patent applies preliminary action by detecting the turn-on state of power transistors before they actually turn on, using sensing transistors that anticipate the switching event. The sensing transistors are activated in advance by the control signal, allowing the circuit to verify the turn-off state of complementary transistors before enabling the main power transistor turn-on, thus preventing cross-conduction before it occurs.

The patent uses sensing transistors as intermediary elements between the control signal and the main power transistors. These sensing transistors act as mediators that detect and report the turn-on state, enabling the control logic to make informed decisions about when to enable the main switching devices without direct coupling between the control signal and power transistors.

The patent employs sensing transistors that are scaled-down copies of the main power transistors, typically with dimensions reduced by a factor of 10 to 100 times. These copying transistors replicate the electrical characteristics and switching behavior of the power transistors but at a much smaller scale, allowing accurate detection of turn-on states without requiring large-area high-voltage comparators.

The patent changes the physical parameters of the sensing transistors, specifically their dimensions, to be fractionally scaled compared to the power transistors. This parameter change allows the sensing transistors to operate at lower voltages and consume less power while maintaining proportional detection accuracy, avoiding the need for high-voltage comparator circuits.