38 V, 5 W synchronous iso-buck converter evaluation board with dual isolated outputs based on L6986I

The STEVAL-L6986IV1 evaluation board is based on L6986I 38 V, 5 W synchronous step-down switching regulator designed for isolated buck topology.
[STEVAL-L6986IV1 IMAGE]
The primary output voltage can be accurately adjusted, whereas the isolated secondary output is generated by using a transformer. No optocoupler is required.
The primary sink capability (typ. 1.9 A) allows proper energy transfer to the secondary side as well as a tracked soft-start of the secondary output. The control loop is based on a peak current mode architecture and the device operates in forced PWM.
The 300 ns blanking time filters oscillations generated by the transformer leakage inductance, making the solution more robust. Pulse by pulse current sensing on both power elements implements an effective constant current protection on the primary side. Thanks to the primary reverse current limit, the secondary output is protected against short-circuit.
The secondary voltage is stabilized over current by using a power transistor and a shunt voltage reference (TL431AIL3T).
The STEVAL-L6986IV1 evaluation board generates two isolated voltages (positive around 18 V and negative between 4 and 5 V), particularly suitable for supplying the IGBT/SiC MOSFET gate driver for multiple applications. A simple by-pass enables the supply of a single isolated voltage.

所有功能
Designed for iso-buck topology
4 to 38 V operating input voltage
Primary output voltage regulation/no optocoupler required
1.9 A typical sink peak primary current capability
Peak current mode architecture in forced PWM operation
300 ns blanking time
8 µA IQ-SHTDWN
Adjustable fSW and synchronization
Embedded primary output voltage supervisor
Adjustable soft-start time
Internal primary current limiting
Overvoltage protection
RDS(on) HS = 180 mΩ, RDS(on) LS = 150 mΩ
Thermal shutdown