Compact low-ripple buck LED driver IC
Rev. 1 — 15 October 2014
Preliminary data sheet
1. General description
The SSL5021BTS is a highly integrated, high-precision, non-isolated MOSFET/bipolar
buck controller. It is intended to drive LED lamps in universal mains non-dimmable lighting
applications up to 25 W. The SSL5021BTS is designed for low-ripple applications.
The SSL5021BTS operates in Boundary Conduction Mode (BCM) with on-time regulation.
Operating in BCM provides a constant output current control with high accuracy. Adaptive
switching frequency gives freedom to choose the inductor, which enables the optimization
of inductor size, efficiency and EMI.
The SSL5021BTS starts up and operates in switching mode directly from an external
resistor without dV/dt supply or auxiliary supply. This feature simplifies the VCC supply. It
allows a low-cost off-the-shelf inductor to be used, providing flexibility in application
The SSL5021BTS comes in a compact TSOP6 package.
The SSL5031BTS is suitable for high power factor/Low THD applications with a
high-temperature foldback function. The SSL5031CTS is best for high power
factor/low THD applications without a high-temperature foldback function.
2. Features and benefits
Driving LED strings from a rectified mains supply, low-ripple (< ±5 %)
Small electronic Bill of Materials (BOM) enabling a compact solution and a small,
single layer Printed-Circuit Board (PCB) footprint
Excellent line and load regulation and LED output current accuracy
Efficient BCM operation with:
No reverse recovery losses in freewheel diode
Zero Current Switching (ZCS) and valley switching for switch turn-on
Minimal inductance value and size required
High efficiency (up to 93 %)
Ultra low IC current during operation (< 150 A)
Many auto-recovery protections:
UnderVoltage LockOut (UVLO)
Cycle-by-cycle OverCurrent Protection (OCP)
Internal OverTemperature Protection (OTP)
Output OverVoltage Protection (OVP)
Output Short Protection (OSP)