SLUA669B March 2013 – September 2023 LM5112 , LM5112-Q1 , LM5114 , LM5134 , LMG1020 , LMG1025-Q1 , SM74101 , TPS2818-EP , TPS2819-EP , TPS2828 , TPS2829 , UC1705 , UC1705-SP , UC1710 , UC2705 , UC3710 , UCC27321 , UCC27321-Q1 , UCC27322 , UCC27322-EP , UCC27322-Q1 , UCC27332-Q1 , UCC27511 , UCC27511A , UCC27511A-Q1 , UCC27512 , UCC27512-EP , UCC27516 , UCC27517 , UCC27517A , UCC27517A-Q1 , UCC27518 , UCC27518A-Q1 , UCC27519 , UCC27519A-Q1 , UCC27531 , UCC27531-Q1 , UCC27532 , UCC27532-Q1 , UCC27533 , UCC27536 , UCC27537 , UCC27538 , UCC27611 , UCC27614 , UCC27614-Q1 , UCC37321 , UCC37322 , UCC44273 , UCC57102 , UCC57102-Q1 , UCC57108 , UCC57108-Q1 , UCD7100
Signal Isolation
The input signals of U1 are isolated in Figure 2-5, with the isolated gate driver, UCC53xx. The isolated bias, a transformer, allows the gate signal to Q1 to have a floating reference that can move as the switch-node moves in voltage.
High-Side Bias
In Figure 2-5, signal isolation is not needed because the gate drivers provide this internally. In this configuration, a bootstrap supply is not needed because of the isolated bias. Vbias1, referenced to power ground, supplies the floating bias for the high-side.