MAX17598 Datasheet, PDF(1/25 Page) Maxim Integrated Products – Low IQ, Wide-Input Range, Active Clamp Current-Mode PWM Controllers

19-6179; Rev 0; 1/12

EVALUATION KIT AVAILABLE

MAX17598 / MAX17599

Low IQ, Wide-Input Range, Active Clamp

Current-Mode PWM Controllers

General Description

Benefits and Features

The MAX17598/MAX17599 low IQ, active clamp current-

mode PWM controllers contain all the control circuitry

required for the design of wide-input isolated/non-iso-

lated forward-converter industrial power supplies. The

MAX17598 is well-suited for universal input (rectified 85V

AC to 265V AC) or telecom (36V DC to 72V DC) power

supplies. The MAX17599 is optimized for low-voltage

industrial supplies (4.5V DC to 36V DC).

The devices include an AUX driver that drives an aux-

iliary MOSFET (clamp switch) that helps implement the

active-clamp transformer reset topology for forward con-

verters. Such a reset topology has several advantages

including reduced voltage stress on the switches, trans-

former size reduction due to larger allowable flux swing,

and improved efficiency due to elimination of dissipative

snubber circuitry. Programmable dead time between the

AUX and main driver allows for zero voltage switching (ZVS).

The switching frequency is programmable from 100kHz

to 1MHz for the devices with an accuracy of Q5% using

an external resistor. This allows the optimization of the

magnetic and filter components, resulting in compact,

cost-effective isolated/nonisolated power supplies. For

EMI-sensitive design, the ICs incorporate a program-

mable frequency dithering feature and enables low EMI

spread-spectrum operation.

An input undervoltage lockout (EN/UVLO) is provided

for programming the input-supply start voltage, and to

ensure proper operation during brownout conditions. The

EN/UVLO input is also used to turn on/off the ICs. Input

overvoltage (OVI) protection scheme is provided to make

sure that the regulator shuts down when the input supply

exceeds its maximum allowed value.

To control inrush current, the devices incorporate an SS

pin to set the soft-start time for the regulator. Power dis-

sipation under fault conditions is minimized by a hiccup

overcurrent protection (hiccup mode). A soft-stop feature

provides safe discharging of the clamp capacitor when the

device is turned off, and allows the controller to restart in a

well-controlled manner. Additionally, a negative current limit

is provided in the current-sense circuitry, helping limit the

clamp switch current under dynamic operating conditions.

A SYNC feature is provided to synchronize multiple convert-

ers to a common external clock in noise-sensitive applica-

tions. Overtemperature faults trigger a thermal shutdown for

reliable protection of the device. The ICs are available in a

16-pin, TQFN package with 0.5 mm lead spacing.

S Active Clamp, Peak Current-Mode Forward PWM

Controller

S 20FA Startup Current in UVLO

S 4.5V to 36V Input-Supply Operating Range

(MAX17599)

S Programmable Input Undervoltage Lockout

S Programmable Input Overvoltage Protection

S Programmable 100kHz to 1MHz Switching

Frequency

S Switching Frequency Synchronization

S Programmable Frequency Dithering for Low EMI

Spread-Spectrum Operation

S Programmable Dead Time

S Adjustable Soft-Start

S Programmable Slope Compensation

S Fast Cycle-by-Cycle Peak-Current-Limit 40ns

Typical Propagation Delay

S 70ns Internal Leading-Edge Current-Sense

Blanking

S Hiccup Mode Output Short-Circuit Protection

S Soft-Stop for Well-Controlled Clamp Capacitor

Discharge

S Negative Current Limit to Limit Clamp-Switch

Clamp Capacitor and Transformer Reverse Current

S 3mm x 3mm, Lead-Free 16-Pin TQFN

Applications

Telecom and Datacom Power Supplies

Isolated Battery Chargers

Servers and Embedded Computing

Industrial Power Supplies

Ordering Information appears at end of data sheet.

For related parts and recommended products to use with this part,

refer to www.maxim-ic.com/MAX17598.related.

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maximâs website at www.maxim-ic.com.

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