Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - voltage regulators - DC DC switch controllers SOIC 8

General Description

The MAX5014/MAX5015 integrate all the building

blocks necessary for implementing DC-DC fixed-fre-

quency isolated power supplies. These devices are

current-mode controllers with an integrated high-volt-

age startup circuit suitable for isolated telecom/industri-

al voltage range power supplies. Current-mode control

with leading-edge blanking simplifies control-loop

design and internal ramp compensation circuitry stabi-

lizes the current loop when operating at duty cycles

above 50% (MAX5014). The MAX5014 allows 85%

operating duty cycle and could be used to implement

flyback converters, whereas the MAX5015 limits the

operating duty cycle to less than 50% and can be used

in single-ended forward converters. A high-voltage

startup circuit allows these devices to draw power

directly from the 18V to 110V input supply during start-

up. The switching frequency is internally trimmed to

275kHz ±10%, thus reducing magnetics and filter com-

ponent costs.

The MAX5014/MAX5015 are available in 8-pin SO

packages. An evaluation kit (MAX5015EVKIT) is also

available.

Warning: The MAX5014/MAX5015 are designed to

operate with high voltages. Exercise caution.

Applications

Telecom Power Supplies

Industrial Power Supplies

Networking Power Supplies

Isolated Power Supplies

Features

♦ Wide Input Range: (18V to 110V) or (13V to 36V)

♦ Current-Mode Control

♦ Leading-Edge Blanking

♦ Internally Trimmed 275kHz ±10% Oscillator

♦ Low External Component Count

♦ Soft-Start

♦ High-Voltage Startup Circuit

♦ Pulse-by-Pulse Current Limiting

♦ Thermal Shutdown

♦ SO-8 Package

MAX5014/MAX5015

Current-Mode PWM Controllers with Integrated

Startup Circuit for Isolated Power Supplies

________________________________________________________________ Maxim Integrated Products 1

GND

NDRVV

OPTO

V+

8-SO

TOP VIEW

MAX5014/

MAX5015

SS_SHDN

Pin Configuration

Ordering Information

MAX5015

V+

SS_SHDN

NDRV

GND

OPTO

OUT

OPTOCOUPLER

Typical Operating Circuit

19-2082; Rev 0; 7/01

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.

EVALUATION KIT

AVAILABLE

PART TEMP. RANGE PIN-PACKAGE

MAX5014CSA* 0°C to +70°C8-SO

MAX5014ESA* -40°C to +85°C8-SO

MAX5015CSA* 0°C to +70°C8-SO

MAX5015ESA* -40°C to +85°C8-SO

*See Selector Guide at end of data sheet.

Summary of content (14 pages)

PAGE 1
KIT ATION EVALU E L B AVAILA 19-2082; Rev 0; 7/01 Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies The MAX5014/MAX5015 are available in 8-pin SO packages. An evaluation kit (MAX5015EVKIT) is also available. Warning: The MAX5014/MAX5015 are designed to operate with high voltages. Exercise caution.
PAGE 2
MAX5014/MAX5015 Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies ABSOLUTE MAXIMUM RATINGS V+ to GND ……………………………………...……-0.3V to +120V VDD to GND.………………………………….……….-0.3V to +40V VCC to GND.………………….……………………-0.3V to +12.5V OPTO, NDRV, SS_SHDN, CS to GND .……-0.3V to VCC + 0.3V VDD and VCC Current …………………...…………………..20mA NDRV Current Continuous...………………………………….25mA NDRV Current for Less than 1µs..………….…………….
PAGE 3
Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies (VDD = 13V, a 10µF capacitor connects VCC to GND, VCS = 0, V+ = 48V, 0.1µF capacitor connected to SS_SHDN, NDRV = open circuit, OPTO = GND, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 4
Typical Operating Characteristics (continued) (V+ = 48V, VDD = 13V, NRDV is open circuit, TA = +25°C, unless otherwise noted.) V+ SUPPLY CURRENT vs. TEMPERATURE 47.4 47.2 47.0 1.43 1.42 1.41 1.40 1.39 0 20 60 V+ INPUT CURRENT vs. TEMPERATURE (AFTER STARTUP) V+ SHUTDOWN CURRENT vs. TEMPERATURE 40 60 80 MAX5014 toc07 11.25 11.20 11.15 V+ = 110V, VOPTO = 4V, CS = GND, VDD = 13V 11.10 11.05 4.80 4.75 VDD = 0, V+ = 110V, OPTO = CS = SS_SHDN = GND 4.70 4.65 4.
PAGE 5
Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies MAX5015 MAXIMUM DUTY CYCLE vs. VDD 269.0 268.5 VOPTO = 4V, CS = GND 268.0 VOPTO = 4V, CS = GND 47.6 47.5 DRIVER POWERED FROM VDD 47.4 47.3 267.5 47.1 267.0 47.0 10 15 20 25 30 35 9.8 9.6 DEVICE POWERED FROM V+ 9.5 0 40 9.9 9.7 DRIVER POWERED FROM V+ 5 10 15 20 25 30 35 40 0 5 10 15 VDD (V) VDD (V) 25 30 35 40 V+ INPUT CURRENT vs. VOLTAGE (AFTER STARTUP) 1.
PAGE 6
Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies MAX5014/MAX5015 Pin Description PIN NAME FUNCTION V+ High-Voltage Startup Input. Connect directly to an input voltage between 18V to 110V. Connects internally to a high-voltage linear regulator that generates VCC during startup. 2 VDD VDD is the Input of the Linear Regulator that Generates VCC. For supply voltages less than 36V, VDD and V+ can both be connected to the supply.
PAGE 7
Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies MAX5014/MAX5015 VDD VDD-OK V+ IN IN HIGHVOLTAGE REGULATOR GND EN BIAS WINDING REGULATOR OUT EN OUT 0.7V VCC UVLO MAX5014 ONLY 6.6V 275kHz OSCILLATOR SLOPE COMPENSATION 26mV/µs R NDRV Q 80%/50% DUTY CYCLE CLAMP 26mV/µs S ∑ ILIM PWM 125mV CS OPTO 5kΩ Vb SS_SHDN 70ns BLANKING 4µA 3R 2.4V BUF R 0.4V Figure 1.
PAGE 8
MAX5014/MAX5015 Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies 4.7nF 250VAC 1N4148 CDD 47µF VOUT CIN 3 × 0.47µF V+ VDD SBL204OCT 14 NR CMHD2003 6 NT VIN (36V TO 72V) NP 14 L1 4.7µH COUT 3 × 560µF 20Ω NS 5 M1 IRF640N 5V/10A 0.1µF 1nF NDRV 100Ω CS RSENSE 100mΩ MAX5015 GND SS_SHDN VCC 220Ω CCC 10µF CSS 0.1µF 4.75kΩ OPTO OPTOCOUPLER R1 25.5kΩ 3kΩ 0.1µF 240kΩ TLV431 R2 8.25kΩ Figure 2.
PAGE 9
Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies MAX5014/MAX5015 4.7nF 250VAC NT VIN VOUT CDD CIN V+ VDD COUT NP NS M1 NDRV 100Ω CS RSENSE MAX5014 GND SS_SHDN VCC CCC CSS 220Ω OPTO OPTOCOUPLER R1 TLV431 R2 Figure 3. Flyback Converter To reduce power dissipation the high-voltage regulator is disabled when the VDD voltage reaches 12.7V. This greatly reduces power dissipation and improves efficiency.
PAGE 10
MAX5014/MAX5015 Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies tstartup = 0.45 ms × Css nF where CSS is the soft-start capacitor as shown in Figure 2. Operation begins when VSS_SHDN ramps above 0.6V. When soft-start has completed, VSS_SHDN is regulated to 2.4V, the internal voltage reference. Pull VSS_SHDN below 0.25V to disable the controller. Undervoltage lockout shuts down the controller when VCC is less than 6.6V.
PAGE 11
Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies where VREF is the reference voltage of the shunt regulator, and R1 and R2 are the resistors shown in Figures 2 and 3. 3) The turns ratio of the transformer is calculated based on the minimum input voltage and the lower limit of the maximum duty cycle for the MAX5015 (44%). To enable the use of MOSFETs with drain-source breakdown voltages of less than 200V use the MAX5015 with the 50% maximum duty cycle.
PAGE 12
Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies MAX5014/MAX5015 ing equation to calculate the tertiary winding turns ratio: where VD is the output Schottky diode forward voltage drop (0.5V) and LIR is the ratio of inductor ripple current to DC output current. VDDMIN + 0.7 × NP ≤ NT ≤ VIN_MIN VDDMAX + 0.7 × NP VIN_MAX where: VDDMIN is the minimum VDD supply voltage (13V). VDDMAX is the maximum VDD supply voltage (36V). VIN_MIN is the minimum input voltage (36V).
PAGE 13
Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies MAX5014/MAX5015 Table 1. Component Manufacturers International Rectifier Power FETS Current-Sense Resistors Diodes Capacitors Magnetics www.irf.com Fairchild www.fairchildsemi.com Vishay-Siliconix www.vishay.com/brands/siliconix/main.html Dale-Vishay www.vishay.com/brands/dale/main.html IRC www.irctt.com/pages/index.cfm On Semi www.onsemi.com General Semiconductor www.gensemi.
PAGE 14
Current-Mode PWM Controllers with Integrated Startup Circuit for Isolated Power Supplies SOICN.EPS MAX5014/MAX5015 Package Information 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.