TDHBG1200DC100-KIT Transphorm

User Guide TDHBG1200DC100: 1.2 kW Half-bridge Evaluation Board Introduction The TDHBG1200DC100 half-bridge evaluation board provides the elements of a simple buck or boost converter, using the Transphorm Daughter Card TDHB-65H070L-DC for basic study of switching characteristics and efficiency achievable with Transphorms 650V GaN FETs in the standard 8x8 PQFN package. In either buck or boost mode the circuit can be configured for synchronous rectification. Jumpers allow use of a single logic input or separate hi/lo inputs. The high-voltage input and output can operate at up to 400Vdc, with a power output of up to 1.2kW. The inductor provided is intended for efficient operation at 100kHz, although other inductors and other frequencies may be easily used. The TDHBG1200DC100-KIT is for evaluation purposes only. Figure 1A Figure 1B. TDHBG1200DC100 half-bridge evaluation board Figure 2 TDHB-65H070L-DC daughter card April 20, 2019 2019 Transphorm Inc. Subject to change without notice. 1 TDHBG1200DC100 User Guide Warnings TDHGB1200DC100 input/output specifications High-voltage input/output: 400Vdc max Auxiliary supply (J1): 10V min, 18V max Logic inputs: nominal 0V-5V Pulse-generation circuit: Vlo < 1.5V, Vhi > 3.0V Direct connection to gate driver: Vlo < 0.8V, Vhi > 2.0V SMA coaxial connectors Switching frequency: configuration-dependent Lower limit determined by peak inductor current Upper limit determined by desired dead-time and power dissipation Power dissipation in the GaN FET is limited by the maximum junction temperature. Refer to the TP65H070LxG datasheets. Circuit description The circuit comprises a simple half-bridge featuring 1 TP65H070LDG and 1 TP65H070LSG GaN FETs, as indicated in the block diagram of Figure 3. Two high-voltage ports are provided which can serve as either input or output, depending on the configurationboost or buck. In either case one FET acts as the active power switch while the other carries the freewheeling current. The latter device may be enhanced, as a synchronous rectifier, or not. With GaN FETs the reverse recovery charge is low and there is no need for additional freewheeling diodes. Two input connectors are provided which can be connected to sources of logic-level command signals for the hi/lo gate driver. Both inputs may be driven by off-board signal sources or alternatively, a single signal source may be connected to an on-board pulse-generator circuit which generates the two non-overlapping pulses. Jumpers determine how the input signals are used. An inductor is provided as a starting point for investigation. This is a 440H toroid intended to demonstrate a reasonable compromise between size and efficiency for power up to 1.2kW at a switching frequency of 100kHz. TDHBG1200DC100 0v1 April 23, 2019 transphormusa.com 2