ZSLS7025 Datasheet

© 2016 Integrated Device Technology, Inc.

9

April 20, 2016

2

Circuit Description

2.1

ZSLS7025 Overview

The ZSLS7025 is a constant current boost converter. Its output current is adjustable via an external current sense

resistor, and it can deliver stable constant output current from a few milliamps up to 2A or higher.

The ZSLS7025 drives a constant current into the load, automatically adjusting the output voltage according to the

load. The control loop features a pulse frequency modulated (PFM) architecture that is inherently stable and does not

need loop compensation.

can be supported if logic level MOSFETs for the higher voltage rating are available. An integrated over-voltage

protection (OVP) circuit protects the system, even under no-load conditions. The over-voltage protection is adjustable

See section 4.2 for requirements for selecting the external components referred to in the following sections.

Figure 2.1

Typical ZSLS7025 Circuit Diagram

TOFF

GATE

ZSLS7025

LED

String

OVP

GND

VDD

ADJ

FB

CS

2.2

Boost Converter

The ZSLS7025's boost converter uses a peak-current mode topology. The CS pin voltage in conjunction with the

been switched on, a blanking timer disables the current sense input CS to avoid immediate spurious shut-off as a

polarity, providing the voltage boost, and the inductor current will decrease until the input voltage on the FB pin drops

and this operation repeats in each cycle.