PMP7993.2: ±5 @ 100mA, ±15V @ 50mA, 7 ~ 32V in

Summary

This Flybuck reference design uses the LM5017 buck regulator to generate four isolated outputs: ±15V@50mA and ±5V@100mA. The regulation is done on the primary side, and thus no opto-coupler is needed. The overall load/line regulation for each output is within +/-5%. The input voltage range is from 17V to 32V. It's suitable for applications requiring multiple positive and negative bias voltage rails.

The LM5017 is a 100 V, 600 mA synchronous step- down regulator with integrated high side and low side MOSFETs. The constant-on-time (COT) control scheme employed in the LM5017 requires no loop compensation, provides excellent transient response, and enables very low step-down ratios. The on-time varies inversely with the input voltage resulting in nearly constant frequency over the input voltage range. A high voltage startup regulator provides bias power for internal operation of the IC and for integrated gate drivers.

Specifications

Manufacturer	Texas Instruments
Category	AC/DC and DC/DC Conversion
Sub-Category	DC/DC SMPS - Multi Output
Eval Board	Board not Stocked
Topology	Step Down
Outputs and Type	4 Isolated
Voltage Out: Highest Current First	±5V, ±15V
Current Out	100mA, 50mA
Voltage In	17 ~ 32 V
Efficiency @ Conditions	>75%, 24V in, 80 ~ 100% load >75%, 17V in, 75 ~ 100% load >70%, 32V in, 65 ~ 100% load
Voltage Out Range	- Fixed
Features	Current Limit (Adj. or Fixed) Shutdown, Enable, Standby Thermal Protection Under Voltage Protection, Brown-Out
Switching Frequency	260 kHz
Standby Current [Typical]	50 µA
Quiescent Current [Typical]	1.75 mA
Component Count + Extras	30 + 13
Internal Switch	Yes
Design Author	Texas Instruments
Application / Target Market	Automotive Power: Auxiliary Power Supply RF: Metering Telecom
Standby Current [Maximum]	225 µA
Quiescent Current [Maximum]	- Not Given
Main I.C. Base Part	LM5017
Date Created By Author	2013-08
Date Added To Library	2014-12