Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - voltage regulators - DC DC switch controllers SO 16

General Description

The MAX5003 high-voltage switching power-supply

controller has all the features and building blocks need-

ed for a cost-effective flyback and forward voltage-

mode control converter. This device can be used to

design both isolated and nonisolated power supplies

with multiple output voltages that operate from a wide

range of voltage sources. It includes a high-voltage

internal start-up circuit that operates from a wide 11V to

110V input range. The MAX5003 drives an external N-

channel power MOSFET and has a current-sense pin

that detects overcurrent conditions and turns off the

power switch when the current-limit threshold is

exceeded. The choice of external power MOSFET and

other external components determines output voltage

and power.

The MAX5003 offers some distinctive advantages: soft-

start, undervoltage lockout, external frequency synchro-

nization, and fast input voltage feed-forward. The

device is designed to operate at up to 300kHz switch-

ing frequency. This allows use of miniature magnetic

components and low-profile capacitors. Undervoltage

lockout, soft-start, switching frequency, maximum duty

cycle, and overcurrent protection limit are all adjustable

using a minimum number of external components. In

systems with multiple controllers, the MAX5003 can be

externally synchronized to operate from a common sys-

tem clock.

Warning: The MAX5003 is designed to operate with

high voltages. Exercise caution.

The MAX5003 is available in 16-pin SO and QSOP pack-

ages. An evaluation kit (MAX5003EVKIT) is also available.

Applications

Telecommunication Power Supplies

ISDN Power Supplies

+42V Automobile Systems

High-Voltage Power-Supply Modules

Industrial Power Supplies

Features

♦ Wide Input Range: 11V to 110V

♦ Internal High-Voltage Startup Circuit

♦ Externally Adjustable Settings

Output Switch Current Limit

Oscillator Frequency

Soft-Start

Undervoltage Lockout

Maximum Duty Cycle

♦ Low External Component Count

♦ External Frequency Synchronization

♦ Primary or Secondary Regulation

♦ Input Feed-Forward for Fast Line-Transient

Response

♦ Precision ±2.5% Reference over Rated

Temperature Range

♦ Thermal Shutdown

MAX5003

High-Voltage PWM

Power-Supply Controller

________________________________________________________________ Maxim Integrated Products 1

V+ V

NDRV

PGND

AGND

MAXTON

TOP VIEW

MAX5003

QSOP/Narrow SO

INDIV

REF

FREQ

CON

COMP

19-1555; Rev 2; 4/02

PART

MAX5003CEE

MAX5003CSE

MAX5003EEE -40°C to +85°C

0°C to +70°C

TEMP. RANGE PIN-PACKAGE

16 QSOP

16 Narrow SO

16 QSOP

EVALUATION KIT

AVAILABLE

Note: Dice are designed to operate over a -40°C to +140°C junc-

tion temperature (T

) range, but are tested and guaranteed at

= +25°C.

Pin Configuration

Ordering Information

MAX5003ESE -40°C to +85°C 16 Narrow SO

MAX5003C/D (Note A) Dice

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Summary of content (16 pages)

PAGE 1
9-1555; Rev 2; 4/02 KIT ATION EVALU E L B AVAILA High-Voltage PWM Power-Supply Controller General Description The MAX5003 offers some distinctive advantages: softstart, undervoltage lockout, external frequency synchronization, and fast input voltage feed-forward. The device is designed to operate at up to 300kHz switching frequency. This allows use of miniature magnetic components and low-profile capacitors.
PAGE 2
MAX5003 High-Voltage PWM Power-Supply Controller ABSOLUTE MAXIMUM RATINGS V+ to GND ............................................................-0.3V to +120V ES to GND ..............................................................-0.3V to +40V VDD to GND ............................................................-0.3V to +19V VCC to GND .........................................................-0.3V to +12.5V MAXTON, COMP, CS, FB, CON to GND..................-0.3V to +8V NDRV, SS, FREQ to GND ............
PAGE 3
High-Voltage PWM Power-Supply Controller (V+ = VES = VDD = +12V, VINDIV = 2V, VCON = 0, RFREQ = RMAXTON = 200kΩ, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETERS SYMBOL CONDITIONS MIN TYP MAX UNITS 100 120 mV +1 µA CURRENT LIMIT CS Threshold Voltage VCS VCON = 1.25V 80 CS Input Bias Current ICS 0 < VCS < 0.
PAGE 4
ELECTRICAL CHARACTERISTICS (continued) (V+ = VES = VDD = +12V, VINDIV = 2V, VCON = 0, RFREQ = RMAXTON = 200kΩ, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETERS SYMBOL CONDITIONS MIN TYP MAX UNITS 500 kΩ PWM OSCILLATOR MAXTON Resistor Range RMAXTON Maximum On-Time Range tON 50 7.5 RMAXTON = 200kΩ, VINDIV = 1.25V µs Input Voltage Feed Forward Ratio VINDIV stepped from 1.5V to 1.875V, VCON = 3.0V (Note 3) 0.72 0.8 0.88 RAMP Voltage Low VINDIV = 1.
PAGE 5
High-Voltage PWM Power-Supply Controller V+ INPUT CURRENT vs. TEMPERATURE 2.5 MAXIMUM DUTY CYCLE vs. VINDIV MAX5003-05 MAX5003-04 2.50 80 400kΩ 70 300kΩ 2.00 MAX5003-06 V+ INPUT CURRENT vs. VOLTAGE 3.0 60 1.50 1.00 VCON = VCOMP = VFB SWITCHING 60 80 100 -20 0 20 40 60 80 100 V+ (V) TEMPERATURE (°C) ERROR AMP FREQUENCY RESPONSE SWITCHING FREQUENCY AND PERIOD vs.
PAGE 6
Typical Operating Characteristics (continued) (VDD = +12V, RFREQ = 200kΩ, RMAXTON = 200kΩ, TA = +25°C, unless otherwise noted.) 350 9 MAX SWITCHING FREQUENCY (kHz) MAX5003-12 10 8 7 6 5 4 3 2 V+ = VES = 12V TO 36V VDD = UNCONNECTED 1 0 300 30nC MAX5003-13 MAXIMUM FREQUENCY vs.
PAGE 7
High-Voltage PWM Power-Supply Controller PIN NAME FUNCTION 11 AGND 12 CS 13 PGND Power Ground. Connect to AGND. 14 NDRV Gate Drive for External N-Channel Power FET 15 VCC Output Driver Power-Rail Decoupling Point. Connect a capacitor to PGND with half the value used for VDD bypass very close to the pin. If synchronizing several controllers, power the fan-out buffer driving the FREQ pins from this pin. 16 VDD 9.75V Internal Linear-Regulator Output. Drive VDD to a voltage higher than 10.
PAGE 8
MAX5003 High-Voltage PWM Power-Supply Controller VFETBIAS V+ MAX5003 HIGH-VOLTAGE EPIFET 1 LINEAR VES REGULATOR VDD 16 VDD 15 VCC 14 NDRV 13 PGND 12 CS 11 AGND 10 MAXTON AGND VDD CC AGND INDIV 2 1.2V ES LINEAR VDD REGULATOR VCC VINOK VCCOK AGND VINOK UV LOCKOUT VCC REF REFOK BANDGAP REFERENCE SDN AGND 3 “1” VCC FREQ 4 D “D”FF CLK Q CLK FREQ DRIVER NDRV R REFOK PGND SDN INDIV SS 5 VCC RAMP CURRENT SENSE MAXTON VCC AGND C LIMIT REF 0.
PAGE 9
High-Voltage PWM Power-Supply Controller Undervoltage Lockout, Feed Forward, and Shutdown The undervoltage lockout feature disables the controller when the voltage at INDIV is below 1.2V (120mV hysteresis). When INDIV rises higher than 1.2V plus the hysteresis (typically 1.32V), it allows the controller to start. An external resistive divider connected between the power line and AGND generates the INDIV signal. INDIV is also used as the signal for the fast input voltage feed-forward circuit.
PAGE 10
MAX5003 High-Voltage PWM Power-Supply Controller It also determines power-up sequencing when several converters are used. Upon power turn-on, the SS pin acts as a current sink to reset any capacitance attached to it. Once REF has exceeded its lockout value, SS sources a current to the external capacitor, allowing the converter output voltage to ramp up. Full output voltage is reached in approximately 0.45s/µF. The SS pin is an overriding extra input to the PWM comparator.
PAGE 11
High-Voltage PWM Power-Supply Controller The driver can source up to 560mA and sink up to 1A transient current with a typical on source resistance of 4Ω. The no-load output levels are VCC and PGND. Applications Information Compensation and Loop Design Considerations The circuit shown in Figure 2 is essentially an energy pump. It stores energy in the magnetic core and the air gap of the transformer while the power switch is on, and delivers it to the load during the off phase.
PAGE 12
MAX5003 High-Voltage PWM Power-Supply Controller +48V (36V TO 72V) XFACOILTRCTX03 VIN 8 2 CMSD4448 LP 65µH 1M 1 2 3 4 5 0.1µF 6 7 8 39k V+ VDD INDIV ES FREQ 7 15 IRFD620S VCC 14 NDRV CS REF AGND CON MAXTON FB 11, 12 +5V 1A MBRS130L 10µF PGND COMP 5 16 MAX5003 SS 4.7µF 0.1µF 33µF 13 12 22µF 11 22µF 100Ω 10 RA 41.2k 9, 10 9 62k 51k 0.1µF 470nF 0.1µF CF 390pF RCS 0.1Ω RF 200k RB 17.4k 0V Figure 2.
PAGE 13
High-Voltage PWM Power-Supply Controller MAX5003 0V XFACOILTRCTX03 CMSD4448 2 LP 65µH 8 IRFD620S R1 1M 4.7µF 7 1 2 3 0.1µF 4 5 6 7 8 R2 39k VDD V+ 5 15 VCC 14 NDRV INDIV ES FREQ 16 PGND SS CS REF AGND CON MAXTON COMP FB +5V 1A 11, 12 10µF MAX5003 MBRS130L 33µF 0.1µF 13 12 22µF 11 100Ω 51Ω 22µF 9, 10 - 10 9 680Ω 62k 6 240k 7 0.01µF 1 1.3k 5 MDC217 470nF 0.1µF 2 0.1µF 3900pF 24.9k 51k VIN RCS 0.1Ω TL431 24.9k -48V -36V TO -72V Figure 3.
PAGE 14
High-Voltage PWM Power-Supply Controller MAX5003 where: RMAXTON = Resistor between the MAXTON pin and ground VMIN = Minimum power-line voltage VUVL = Power-line trip voltage DCMAX(VMIN) = Maximum duty cycle at minimum power-line voltage For this application circuit, a 10% margin is reasonable, so the value used is 50kΩ. This gives a maximum duty cycle of 50%. The maximum duty cycle can now be expressed as: V - 0.5V  DC(VCON,VIN ) =  CON  2.0V   V - 0.5V  CON ≈  2.
PAGE 15
High-Voltage PWM Power-Supply Controller desired value, the center-point voltage will be 1.5V. The Thevenin equivalent of the resistors must be low enough so the error amplifier bias current will not introduce a division error. The two resistors must have similar temperature coefficients (tempcos), so the dividing ratio will be constant with temperature.
PAGE 16
MAX5003 High-Voltage PWM Power-Supply Controller stress on the switch. A FET with the lowest total charge and the lowest RDS(ON) for the maximum drain voltage expected (plus some safety factor) is the best choice. The choice of package is a function of the application, the total power, and the cooling methods available. Transformer Transformer parameters, once calculated in the design process, can be used to find standard parts whenever possible.