MAX17598_13 Datasheet, PDF (1/24 Pages) Maxim Integrated Products – Low IQ, Wide-Input Range, Active Clamp Current-Mode PWM Controllers

EVALUATION KIT AVAILABLE
MAX17598/MAX17599
Low I_Q, Wide-Input Range, Active Clamp
Current-Mode PWM Controllers
General Description
Benefits and Features
The MAX17598/MAX17599 low I_Q, 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 Q8%
using an external resistor. This allows optimization of
the magnetic and filter components, resulting in com-
pact, cost-effective isolated/nonisolated power supplies.
For EMI-sensitive applications, the ICs incorporate a
programmable frequency-dithering scheme, enabling
low-EMI spread-spectrum operation.
An input undervoltage lockout (EN/UVLO) is provided for
programming input-supply start voltage, and to ensure
proper operation during brownout conditions. 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 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 regulators. Power dissipa-
tion under fault conditions is minimized by hiccup overcur-
rent protection (hiccup mode). 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, negative current limit is
provided in the current-sense circuitry, helping limit clamp
switch current under dynamic operating conditions.
SYNC feature is provided to synchronize multiple convert-
ers to a common external clock in noise-sensitive applica-
tions. Overtemperature fault triggers 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
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 Clamp-Switch Current Limit
S 3mm x 3mm, Lead-Free 16-Pin TQFN
S -40°C to +125°C Operating Temperature Range
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.maximintegrated.com/MAX17598.related.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-6179; Rev 1; 3/13