Diodes brings two ways to time a half bridge to electronica
Diodes Incorporated has released two isolated gate driver families, the API21550 and API21552, and plans to show both in a 48 V converter at electronica. When two switches share a half bridge, the API21550 can hold off the incoming switch until a set interval has elapsed. The API21552 lets the controller time both outputs independently, so the same driver can also serve pairs of switches whose on times can overlap. [1][2][3]
On the API21550, the designer sets that interval with a resistor. The driver enforces the minimum if the incoming commands are closer together, while a controller that has already allowed more dead time can keep its longer interval. Both drivers are rated for up to 4 A peak source and 6 A peak sink current, with 40 ns typical propagation delay. Diodes lists output supplies up to 30 V and offers a choice of undervoltage lockout thresholds to suit different gate drive supplies. [1][2][3]
As the half bridge switches, the isolated control signal has to cross a barrier whose two sides are moving rapidly in voltage relative to one another. Diodes specifies at least 150 V/ns of common mode transient immunity for that condition. For the separate one-minute withstand test under UL 1577, Diodes specifies 5.7 kV RMS in the wide SO-14W and SO-16W packages and 3 kV RMS in the narrower SO-16. [2][3] Diodes lists separate automotive variants, API21550Q and API21552Q, and plans to run the converter demonstration in Hall C6, Booth 211 in Munich. [1]
