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MAX17598 Datasheet

Download or read online Maxim Integrated MAX17598 Low-IQ Wide-Input-Range Active-Clamp Current-Mode PWM Controllers pdf datasheet.



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Low I
Q
General Description
The MAX17598/MAX17599 low I
, active clamp current-
Q
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.
_________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX17598/MAX17599
, Wide-Input Range, Active Clamp
Current-Mode PWM Controllers
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
Telecom and Datacom Power Supplies
Isolated Battery Chargers
Servers and Embedded Computing
Industrial Power Supplies
Ordering Information
For related parts and recommended products to use with this part,
refer to www.maxim-ic.com/MAX17598.related.
19-6179; Rev 0; 1/12
E V A L U A T I O N K I T A V A I L A B L E
Benefits and Features
Applications
appears at end of data sheet.

Summary of Contents

Page 1

... 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 ...

Page 2

... Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V 12V (for MAX17598, bring AUXDRV NDRV SS COMP SLOPE unconnected, R 125NC, unless otherwise noted ...

Page 3

... Low I ELECTRICAL CHARACTERISTICS (continued 12V (for MAX17598, bring AUXDRV NDRV SS COMP SLOPE unconnected, R 125NC, unless otherwise noted. Typical values are at T PARAMETER SYMBOL INTERNAL LDO (V ) DRV V Output Voltage Range DRV V Current Limit I DRV VDRV-MAX V Dropout V DRV VDRV-DO OVERVOLTAGE PROTECTION (OVI) ...

Page 4

... Low I ELECTRICAL CHARACTERISTICS (continued 12V (for MAX17598, bring AUXDRV NDRV SS COMP SLOPE unconnected, R 125NC, unless otherwise noted. Typical values are at T PARAMETER SYMBOL SOFT-START/SOFT-STOP (SS) Soft-Start Charging Current Soft-Stop Discharging I SSDISCH Current SS Bias Voltage SS Discharge Threshold V SSDISCH NDRV DRIVER (NDRV) Pulldown Impedance ...

Page 5

... Low I ELECTRICAL CHARACTERISTICS (continued 12V (for MAX17598, bring AUXDRV NDRV SS COMP SLOPE unconnected, R 125NC, unless otherwise noted. Typical values are at T PARAMETER SYMBOL Current-Sense Leading-Edge t CS-BLANK Blanking Time Current-Sense-Blanking Time t CS-BLANK- for Reverse-Current Limit Propagation Delay from Comparator Input to NDRV ...

Page 6

... Note 2: All devices are 100% production tested at 25NC. Limits over temperature are guaranteed by design. Note 3: The MAX17598 is intended for use in universal input power supplies. The internal clamp circuit used to prevent the bootstrap capacitor from changing to a voltage beyond the absolute maximum rating of the device when EN is low (shut- down mode) ...

Page 7

... DITHER PEAK-CURRENT-LIMIT THRESHOLD vs. TEMPERATURE 307 306 305 304 303 302 301 300 120 -40 - TEMPERATURE (°C) MAX17598/MAX17599 T -40NC to 125NC, unless otherwise noted.) J NDRV SWITCHING FREQUENCY vs. RESISTOR 1000 900 800 700 600 500 400 300 200 100 0 80 100 120 ...

Page 8

... CLAMPCAP 25V/div MAX17598/MAX17599 T -40NC to 125NC, unless otherwise noted REGULATION VOLTAGE vs. TEMPERATURE -40 - 100 120 TEMPERATURE (°C) ENABLE SHUTDOWN WAVEFORM (SOFT-STOP) MAX17598/9 toc16 2ms/div INPUT SHUTDOWN MAX17598/9 toc18 20ms/div V EN/UVLO 5V/div V CLAMPCAP 10V/div V OUT 5V/div V IN 10V/div V OUT 5V/div V ...

Page 9

... V NDRV 5V/div V AUXDRV 5V/div MAX17598/MAX17599 T -40NC to 125NC, unless otherwise noted.) J DEAD TIME BETWEEN NDRV AND AUXDRV MAX17598/9 toc20 40ns 40ns/div AUXDRV PEAK SOURCE AND SINK CURRENTS MAX17598/9 toc22 PEAK SOURCE CURRENT PEAK SINK CURRENT 200ns/div MOMENTARY OVI OPERATION MAX17598/9 toc24 ...

Page 10

... GAIN 10dB/div MAX17598/MAX17599 T -40NC to 125NC, unless otherwise noted EFFICIENCY GRAPH (5V OUTPUT 24V 200 400 600 800 1000 1200 1400 LOAD CURRENT (mA) ACTIVE CLAMP SWITCHING WAVEFORMS MAX17598/9 toc28 1µs/div V DS 20V/div I PRIMARY 0.5A/div ...

Page 11

... PGND Power Ground. Connect PGND to the power ground plane. ___ Maxim Integrated Products 11 MAX17598/MAX17599 , Wide-Input Range, Active Clamp Q Current-Mode PWM Controllers TOP VIEW DRV MAX17598 MAX17599 EN/UVLO 15 EP OVI TQFN FUNCTION Pin Configuration SGND 8 SS ...

Page 12

... PWM controllers contain all the control circuitry required for the design of wide-input isolated/noniso- lated forward converter industrial power supplies. The MAX17598 has a rising UVLO threshold of 20V with a 13V hysteresis, and is therefore well-suited for universal input (rectified 85V AC to 265V AC) or telecom (36V DC to 72V DC) power supplies ...

Page 13

... Low I 7.5V (MAX17598 (MAX17599) 5V DRV LDO LDO AV POK V IN UVLO EN/ UVLO 1.21V OVI 1.21V RT CHIPEN 10µ SSDONE 1.21V 5µA CHIPEN/ HICCUP DITHER 50µA Q (SYNC) 2V/0.4V Figure 1. Block Diagram ___ Maxim Integrated Products 13 MAX17598/MAX17599 , Wide-Input Range, Active Clamp Q Current-Mode PWM Controllers MAX17598 ...

Page 14

... MOSFET drivers internally to the MAX17598/MAX17599. The V voltage is regulated at 7.5V (typical) for the DRV MAX17598, and at 5V (typical) for the MAX17599. The maximum operating voltage of the IN pin is 29V for the MAX17598 and 36V for the MAX17599. Maximum Duty Cycle (Dmax) The MAX17598/MAX17599 operate at a maximum duty cycle of 70% ...

Page 15

... If the voltage V IN exceeds 8V before the voltage on C then the V voltage is sustained ing the MAX17598 to continue to operate with energy from V . The large hysteresis (13V typical) of the BIAS MAX17598 allows for a small startup capacitor (C The low startup current (20FA typical) allows the use of ...

Page 16

... The soft-stop duration is twice that of the programmed soft- start period. Since the MAX17598/MAX17599 operate at a maximum duty cycle of 70%, slope compensation is required to prevent subharmonic instability that occurs naturally in continuous mode, peak current mode-controlled con- verters operating at duty cycles greater than 50% ...

Page 17

... Figure 5. Duty Cycle Soft-Start NDRV AUXDRV CS Figure 6. Duty Cycle or Current Soft-Stop ___ Maxim Integrated Products 17 , Wide-Input Range, Active Clamp Q Current-Mode PWM Controllers SSCH 1.36V COMP V 1.23V - I SS SOFT-STOP BEGINS MAX17598/MAX17599 V - 1.36V COMP SOFT-START ENDS SSDISCH SS SOFT-STOP ENDS 0.4V 0.0V ...

Page 18

... CS source of the n-channel MOSFET and PGND, sets the current limit. The source end of the current-sense resis- tor connects to the CS pin of the MAX17598/MAX17599. The signal thus obtained is used by the devices, both for current-mode control and peak-current limiting purposes. The current-limit comparator has a voltage trip ...

Page 19

... Under these conditions, the primary peak current tends to build up and staircase beyond the peak current limit setting due to insufficient discharging of the output inductor. One single event of a runaway current limit forces the MAX17598/MAX17599 into hiccup mode ___ Maxim Integrated Products 19 , Wide-Input Range, Active Clamp Q Current-Mode PWM Controllers operation ...

Page 20

... The MAX17598/MAX17599 error amp is set- proportional gain amplifier. This is demonstrated in the Typical Application Circuit for the MAX17598/MAX17599. A useful feature of the MAX17598 is the elimination of need for secondary-side soft-start circuitry. In the absence of secondary side soft-start circuitry, the secondary ___ Maxim Integrated Products 20 ...

Page 21

... SW provided under the exposed pad of the part for efficient heat dissipation. For a sample layout that ensures first pass success, please refer to the MAX17598/MAX17599 Evaluation Kit layouts available at www.maxim-ic.com. For universal AC input designs, follow all applicable safety regulations. Offline power supplies can require UL, VDE, and other similar agency approvals ...

Page 22

... R13 10kI D4 PGND R14 100I CS C9 R16 330pF 200mI SGND PGND V DRV V DRV C10 2.2µF R16 PGND 20kI DT EP SGND SGND MAX17598/MAX17599 Typical Application Circuits V OUT L2 4.7µF R17 0I R18 0I C12 Q1 100µF Q2 GND0 Q3 R20 U2 100I V DRV R21 OPEN V FB R19 1.2kI ...

Page 23

... COMP R8 10kI 1.14MI EN /UVLO EN /UVLO R2 109kI OVI OVI R3 50kI SGND SGND ___ Maxim Integrated Products 23 MAX17598/MAX17599 , Wide-Input Range, Active Clamp Q Current-Mode PWM Controllers Typical Application Circuits (continued) T1 R10 0I C6 0.47µF PGND C10 V IN 0.01µF C7 R11 0.01µF 0I AUXDRV R12 ...

Page 24

... Low I PART TEMP RANGE MAX17598ATE -40NC to 125NC MAX17599ATE -40NC to 125NC Denotes a lead(Pb)-free/RoHS-compliant package. ___ Maxim Integrated Products 24 MAX17598/MAX17599 , Wide-Input Range, Active Clamp Q Current-Mode PWM Controllers PIN PACKAGE FUNCTIONALITY Active clamp, peak current mode, 16 TQFN offline PWM controller Active clamp, peak current mode, ...

Page 25

... Maxim reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2012 Maxim Integrated Products MAX17598/MAX17599 , Wide-Input Range, Active Clamp Q Current-Mode PWM Controllers DESCRIPTION Maxim is a registered trademark of Maxim Integrated Products, Inc ...

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