Datasheet

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General Description

The MAX5069 is a high-frequency, current-mode,

pulse-width modulation (PWM) controller (with dual

MOSFET drivers) that integrates all the building blocks

necessary for implementing AC-DC or DC-DC fixed-fre-

quency power supplies. Isolated or nonisolated push-

pull and half/full-bridge power supplies are easily

constructed using either primary- or secondary-side

regulation. Current-mode control with leading-edge

blanking simplifies control-loop design and a program-

mable internal slope-compensation circuit stabilizes the

current loop when operating at duty cycles above 50%.

An input undervoltage lockout (UVLO) programs the

input-supply startup voltage and ensures proper opera-

tion during brownout conditions.

A single external resistor programs the oscillator frequen-

cy from 50kHz to 2.5MHz. The MAX5069A/D provide a

SYNC input for synchronization to an external clock. The

maximum FET-driver duty cycle for the MAX5069 is 50%.

Programmable dead time allows additional flexibility in

optimizing magnetic design and overcoming parasitic

effects. Programmable hiccup current limit provides

additional protection under severe faults.

The MAX5069 is specified over the -40°C to +125°C auto-

motive temperature range and is available in a

16-pin thermally enhanced TSSOP-EP package. Refer to

the MAX5068 data sheet for single FET-driver applications.

Warning: The MAX5069 is designed to work with high

voltages. Exercise caution.

Applications

Universal-Input AC Power Supplies

Isolated Telecom Power Supplies

Networking System Power Supplies

Server Power Supplies

Industrial Power Conversion

Features

♦ Current-Mode Control with 47µA (typ) Startup

Current

♦ Oscillator Frequency Programmable to 2.5MHz

♦ Resistor-Programmable ±4.5% Accurate

Switching Frequency

♦ Dual Gate-Drive Output for Half/Full-Bridge or

Push-Pull Applications

♦ Rectified 85VAC to 265VAC, or 36VDC to 72VDC

Input (MAX5069A/B)

♦ Input Directly Driven from 10.8V to 24V

(MAX5069C/D)

♦ Programmable Dead Time and Slope

Compensation

♦ Programmable Startup Voltage (UVLO)

♦ Programmable UVLO Hysteresis (MAX5069B/C)

♦ Frequency Synchronization Input (MAX5069A/D)

♦ -40°C to +125°C Automotive Temperature Range

♦ 16-Pin Thermally Enhanced TSSOP-EP Package

MAX5069

High-Frequency, Current-Mode PWM Controller

with Accurate Oscillator and Dual FET Drivers

________________________________________________________________ Maxim Integrated Products 1

REG5

NDRVA

NDRVB

PGND

AGND

TOP VIEW

MAX5069

TSSOP-EP

SYNC(HYST*)

SCOMP

UVLO/EN

COMP

FLTINT

*MAX5069B/C.

Pin Configuration

Ordering Information

19-3175; Rev 1; 7/04

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.

*EP = Exposed pad.

PART TEMP RANGE PIN-PACKAGE

MAX5069AAUE

-40°C to +125°C

16 TSSOP-EP*

MAX5069BAUE

-40°C to +125°C

16 TSSOP-EP*

MAX5069CAUE

-40°C to +125°C

16 TSSOP-EP*

MAX5069DAUE

-40°C to +125°C

16 TSSOP-EP*

Selector Guide appears at end of data sheet.

Summary of content (19 pages)

PAGE 1
9-3175; Rev 1; 7/04 High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers The MAX5069 is a high-frequency, current-mode, pulse-width modulation (PWM) controller (with dual MOSFET drivers) that integrates all the building blocks necessary for implementing AC-DC or DC-DC fixed-frequency power supplies. Isolated or nonisolated pushpull and half/full-bridge power supplies are easily constructed using either primary- or secondary-side regulation.
PAGE 2
MAX5069 High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers ABSOLUTE MAXIMUM RATINGS IN to PGND ............................................................-0.3V to +30V IN to AGND.............................................................-0.3V to +30V VCC to PGND..........................................................-0.3V to +13V VCC to AGND..........................................................-0.3V to +13V FB, COMP, CS, HYST, SYNC, REG5 to AGND ........-0.
PAGE 3
High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers (VIN = +12V for the MAX5069C/D, VIN = +23.6V for the MAX5069A/B at startup, then reduces to +12V, CIN = CREG5 = 0.1µF, CVCC = 1µF, RRT = 100kΩ, NDRV_ = floating, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 4
MAX5069 High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers ELECTRICAL CHARACTERISTICS (continued) (VIN = +12V for the MAX5069C/D, VIN = +23.6V for the MAX5069A/B at startup, then reduces to +12V, CIN = CREG5 = 0.1µF, CVCC = 1µF, RRT = 100kΩ, NDRV_ = floating, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 5
High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers MAX5069A/B 21.5 UVLO/EN WAKE-UP THRESHOLD vs. TEMPERATURE MAX5069A/B 1.245 9.9 MAX5069 toc03 10.0 MAX5069 toc01 21.6 BOOTSTRAP UVLO SHUTDOWN LEVEL vs. TEMPERATURE MAX5069 toc02 BOOTSTRAP UVLO WAKE-UP LEVEL vs. TEMPERATURE UVLO/EN RISING 1.240 21.4 UVLO/EN (V) VIN (V) VIN (V) 9.8 21.3 9.7 1.235 1.230 21.2 9.6 21.0 9.5 10 35 60 85 110 1.
PAGE 6
Typical Operating Characteristics (continued) (VIN = +23.6V for MAX5069A/B at startup, then reduces to +12V, VIN = +12V for the MAX5069C/D, CIN = CREG5 = 0.1µF, CVCC = 1µF, RRT = 100kΩ, NDRV_ = floating, VFB = 0V, VCOMP = floating, VCS = 0V, TA = +25°C, unless otherwise noted.) CS TRIP THRESHOLD vs. TEMPERATURE 4.982 4.981 4.980 4.979 4.978 318 315 312 309 fSW = 500kHz 525 +3σ 510 505 MEAN 500 -3σ 495 306 4.976 303 485 4.
PAGE 7
High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers VIN = 24V SINKING 50mA 12.0 11.0 62.5 62.4 10.5 10.0 62.3 9.5 62.2 9.0 62.1 8.5 8.0 62.0 -15 10 35 60 85 -15 10 60 85 TEMPERATURE (°C) TEMPERATURE (°C) 35 110 0.03 50.8 50.4 50.0 49.6 49.2 48.8 504 MAX5069 toc23 51.2 NDRV SWITCHING FREQUENCY (kHz) fSW = 50kHz 1 2 NDRV SWITCHING FREQUENCY vs. TEMPERATURE 505 MAX5069 toc22 52.0 0.1 RRT (MΩ) NDRV SWITCHING FREQUENCY vs.
PAGE 8
MAX5069 High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers Pin Description PIN MAX5069A MAX5069D MAX5069B MAX5069C NAME FUNCTION 1 1 RT Oscillator-Timing Resistor. Connect a resistor from RT to AGND to set the internal oscillator frequency. 2 — SYNC 8 External-Clock Sync Input. Connect SYNC to AGND when not using an external clock.
PAGE 9
High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers The MAX5069 is a current-mode, dual MOSFET driver, PWM controller designed for isolated and nonisolated push-pull or half-/full-bridge power-supply applications. A bootstrap UVLO with a programmable hysteresis, very low startup, and low operating current result in high-efficiency universal-input power supplies.
PAGE 10
MAX5069 High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers D3 D1 VOUT C7 VIN R1 C1 R6 R2 IN D2 UVLO/EN C2 FLTINT RHYST C3 HYST VCC C4 R9 R7 MAX5069B REG5 R3 RT NDRVB Q2 NDRVA R4 R10 Q1 DT CS C5 SCOMP FB R8 AGND PGND COMP R5 C6 Figure 1. Nonisolated Power Supply with Programmable Input Supply Voltage Undervoltage Lockout The MAX5069 features an input voltage UVLO/EN function to enable the PWM controller before any operation can begin.
PAGE 11
High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers MAX5069 VIN MAX5069A/D R6 UVLO/EN VHYST = VON - VOFF R7 1.23V 1.18V VOFF Figure 2. Setting the MAX5069A/D Undervoltage Lockout Threshold hysteresis that allows the user to set a voltage (VOFF) to disable the controller (see Figure 3). At the beginning of the startup sequence, UVLO/EN is below the 1.23V threshold, and Q1 turns on connecting RHYST to GND (Figure 4). Once the UVLO 1.
PAGE 12
MAX5069 High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers MAX5069A/B Startup Operation Normally, VIN is derived from the tertiary winding of the transformer. However, at startup there is no energy delivered through the transformer; hence, a special bootstrap sequence is required. Figure 5 shows the voltages on VIN and VCC during startup. Initially, both VIN and VCC are 0V.
PAGE 13
High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers MAX5069 VOUT C7 VIN R1 C1 R6 R2 IN C2 UVLO/EN FLTINT C3 VCC RHYST MAX5069B HYST R7 C4 REG5 NDRVB R3 Q2 RT NDRVA Q1 R4 DT CS SCOMP FB C5 AGND R12 R8 C8 VCC PGND COMP R5 C10 C6 R13 PS2913 R10 R9 R11 MAX8515 R14 Figure 6. Secondary-Side, Regulated, Isolated Power Supply For example: 24V x 4.
PAGE 14
MAX5069 High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers Oscillator/Switching Frequency Use an external resistor at RT to program the MAX5069 internal oscillator frequency from 50kHz to 2.5MHz. The MAX5069 NDRVA/NDRVB switching frequency is one half of the programmed oscillator frequency with a maximum 50% duty cycle. Use the following formula to calculate the internal oscillator frequency: fosc = Dead time = 11 10 RRT 60 × RDT (ns) 29.
PAGE 15
High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers I x tSH CFLTINT ≅ FLTINT 2.8V where IFLTINT = 60µA, tSH is the desired fault-integration time during which current-limit events from the current-limit comparator are ignored. For example, a 0.1µF capacitor gives a fault-integration time of 4.7ms. This is an approximate formula. Some testing may be required to fine-tune the actual value of the capacitor.
PAGE 16
MAX5069 High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers Current Limit Applications Information The current-sense resistor (RCS), connected between the source of the MOSFET and ground, sets the current limit. The CS input has a voltage trip level (V CS) of 314mV. Use the following equation to calculate the value of RCS: RCS = Layout Recommendations Keep all PC board traces carrying switching currents as short as possible, and minimize current loops.
PAGE 17
R5 R19 C8 R8 C11 C10 PGND R4 R3 MAX5069B PGND FB R10 FLTINT CS AGND NDRVB HYST COMP NDRVA VCC IN REG5 DT SCOMP UVLO/EN RT C12 C1 PGND PGND REG5 C13 PGND PGND C14 R20 PGND R13 R12 R11 C2 C3 R14 PGND R16 Q2 Si7450DP Q1 Si7450DP C4 D5 N4148 D4 N4148 D3 N4148 D2 N4148 R15 R17 6T 6T T1 R21 3T 3T VCC D1 25CTQ45 PS2911 L1 10µH C15 C5 C7 C17 OUT IN FB GND MAX8515AEZK-T R17 C16 PGND C6 R2 R1 VOUT 12V UP TO 15A Typical Operating Circuit __
PAGE 18
High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers MAX5069 Functional Diagram HYST** BOOTSTRAP UVLO MAX5069 UVLO/EN 21.6V/ 9.74V UVLO 1.23V REFERENCE 1.23V/ 1.18V IN VIN CLAMP 26V IN 2.8V/ 1.6V 60µA REGULATOR Q FLTINT REG_OK R S 5V OUT REG5 VCC VCC CURRENT-LIMIT COMPARATOR S 314mV 5kΩ + CS + Σ * 1.6V Q NDRVA R 70ns BLANKING AGND PWM COMPARATOR NDRVB OSC PGND OUT THERMAL SHUTDOWN DEAD TIME SLOPE COMPENSATION SCOMP OUT 1.
PAGE 19
High-Frequency, Current-Mode PWM Controller with Accurate Oscillator and Dual FET Drivers TSSOP 4.4mm BODY.EPS PACKAGE OUTLINE, TSSOP, 4.40 MM BODY EXPOSED PAD 21-0108 D 1 1 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.