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4.5V to 40V Input Automotive Flyback/Boost/SEPIC Power-Supply Controllers

Automotive VFD Power Supply Operates Down to 2.5V Input Voltage After Startup and Includes Output Overvoltage Protection for VFDs

Product Details

The MAX15004/MAX15005 high-performance, current-mode PWM controllers operate at an automotive input voltage range from 4.5V to 40V (load dump). The input voltage can go lower than 4.5V after startup if IN is bootstrapped to a boosted output voltage. The controllers integrate all the building blocks necessary for implementing fixed-frequency isolated/nonisolated power supplies. The general-purpose boost, flyback, forward, and SEPIC converters can be designed with ease around the MAX15004/MAX15005.

The current-mode control architecture offers excellent line-transient response and cycle-by-cycle current limit while simplifying the frequency compensation. Programmable slope compensation simplifies the design further. A fast 60ns current-limit response time, low 300mV current-limit threshold makes the controllers suitable for high-efficiency, high-frequency DC-DC converters. The devices include an internal error amplifier and 1% accurate reference to facilitate the primary-side regulated, single-ended flyback converter or nonisolated converters.

An external resistor and capacitor network programs the switching frequency from 15kHz to 500kHz (1MHz for the MAX15005). The MAX15004A/MAX15005 provide a SYNC input for synchronization to an external clock. The maximum FET-driver duty cycle for the MAX15004A/B/C/D is 50%. The maximum duty cycle can be set on the MAX15005A/B/C/D by selecting the right combination of RT and CT.

The input undervoltage lockout (ON/active-low OFF) programs the input-supply startup voltage and can be used to shutdown the converter to reduce the total shutdown current down to 10µA. Protection features include cycle-by-cycle and hiccup current limit, output overvoltage protection, and thermal shutdown.

The MAX15004/MAX15005 are available in space-saving 16-pin TSSOP and thermally enhanced 16-pin TSSOP-EP packages. All devices operate over the -40°C to +125°C automotive temperature range.

Key Features

  • Wide Supply Voltage Range Meets Automotive Power-Supply Operating Requirement Including "Cold Crank" Conditions
    • 4.5V to 40V Operating Input Voltage Range (Can Operate at Lower Voltage After Startup if Input is Bootstrapped to a Boosted Output)
  • Control Architecture Offers Excellent Performance While Simplifying the Design
    • Current-Mode Control
    • 300mV, 5% Accurate Current-Limit Threshold Voltage
    • Programmable Slope Compensation
    • 50% (MAX15004) or Adjustable (MAX15005) Maximum Duty Cycle
  • Accurate, Adjustable Switching Frequency and Synchronization Avoids Interference with Sensitive Radio Bands
    • Switching Frequency Adjustable from 15kHz to 500kHz (1MHz for the MAX15005A/B/C/D)
    • RC Programmable 4% Accurate Switching Frequency
    • External Frequency Synchronization
  • Built-In Protection Capability for Improved System Reliability
    • Cycle-by-Cycle and Hiccup Current-Limit Protection
    • Overvoltage and Thermal-Shutdown Protection
    • -40°C to +125°C Automotive Temperature Range
    • AEC-Q100 Qualified

Applications/Uses

  • Automotive
  • Isolated Flyback, Forward, Nonisolated SEPIC, Boost Converters
  • Vacuum Fluorescent Display (VFD) Power Supply
Parametric specs for Step-Up (Boost) Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 40
VOUT1 (V) (min) 1.23
VOUT1 (V) (max) 100
IOUT1 (A) (max) 10
Switch Type External
Output Adjust. Method Resistor
Power Good Signal Yes
ICC (mA) (typ) 2
Shutdown Mode Supply Current (µA) (typ) 0.01
Shutdown Mode Supply Current (µA) (max) 0.02
# DC-DC Outputs 1
Switching Frequency (kHz) 1000
Package/Pins TSSOP/16
Budgetary
Price (See Notes)
$1.57 @1k
Parametric specs for Step-Down/Up (Buck Boost) Regulator
VIN (V) (min) 4.5
VIN (V) (max) 40
VOUT1 (V) (min) 1.23
VOUT1 (V) (max) 100
IOUT1 (A) (max) 10
Switch Type External
VOUT1 Tolerance (±%) 1
Output Adjust. Method Resistor
Power Good Signal Yes
ICC (mA) (max) 3.1
# DC-DC Outputs 1
Alternate Topology Inverting
Step-Up
Switching Frequency (kHz) 1000
Package/Pins TSSOP/16
Oper. Temp. (°C) -40 to +125
Budgetary
Price (See Notes)
$1.57 @1k
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Simplified Block Diagram

MAX15004, MAX15005: Functional Diagram MAX15004, MAX15005: Functional Diagram Zoom icon

Technical Docs

Design & Development

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Description

The MAX15005A evaluation kit (EV kit) is a fully assembled and tested PCB that contains an 11W flyback DC-DC converter for vacuum-fluorescent displays (VFDs) in automotive applications. The circuit uses a MAX15005C high-performance, current-mode pulse-width modulation (PWM) controller in a 16-pin TSSOP package. The EV kit circuit is configured for output voltages of 3V, 60V, and 110V, and provides up to 650mA, 12mA, and 55mA of current from the respective output. Additionally, a 5V low-dropout (LDO) voltage regulator output is provided that can source up to 15mA. Power for the EV kit circuit is provided from a 6.5V to 16V DC source. The MAX15005A EV kit input circuit can sustain a 40V transient.

High efficiency of up to 71% is achieved using a single-transistor flyback DC-DC converter topology. Low cost is achieved through the use of direct secondary-side regulation that does not require optical couplers. Input undervoltage lockout (UVLO), output overvoltage protection (OVP), and soft-start provide for a robust 11W power supply.

Operation at 100kHz minimizes the size of the transformer and passive components.

Warning: The MAX15005A EV kit is designed to operate with high voltages. Dangerous voltages are present on this EV kit and on equipment connected to it. Users who power up this EV kit, or power the sources connected to it, must be careful to follow safety procedures appropriate to working with high-voltage electrical equipment.

Under severe fault or failure conditions, this EV kit may dissipate large amounts of power, which could result in the mechanical ejection of a component or of component debris at high velocity. Operate this kit with care to avoid possible personal injury.

View Details

Features

  • 6.5V to 16V DC Input Range
  • Outputs
    • 3V Provides Up to 650mA (VFD Filament)
    • 60V Provides Up to 12mA (VFD Grid)
    • 110V Provides Up to 55mA (VFD Anode)
  • Output Voltage Accuracy
    • 110V (Anode) = ±3% (Regulated Output)
    • 60V (Grid) = ±5% (Proportional Loading)
    • 3V (Filament) = ±10% (Proportional Loading)
  • 71% Efficiency at 16V Input and Full Load
  • 5V LDO Output Provides Up to 15mA
  • Hiccup Current-Limit and Overtemperature Shutdown
  • 100kHz Switching Frequency
  • Capacitor Adjustable Soft-Start
  • High-Accuracy Undervoltage Lockout (UVLO)
  • Output Overvoltage Protection (OVP)
  • Capable of Synchronizing to an External Clock
  • Low-Cost, Robust Flyback Design
  • Fully Assembled and Tested

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Parameters

Parametric specs for Step-Up (Boost) Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 40
VOUT1 (V) (min) 1.23
VOUT1 (V) (max) 100
IOUT1 (A) (max) 10
Switch Type External
Output Adjust. Method Resistor
Power Good Signal Yes
ICC (mA) (typ) 2
Shutdown Mode Supply Current (µA) (typ) 0.01
Shutdown Mode Supply Current (µA) (max) 0.02
# DC-DC Outputs 1
Switching Frequency (kHz) 1000
Package/Pins TSSOP/16
Budgetary
Price (See Notes)
$1.57 @1k
Parametric specs for Step-Down/Up (Buck Boost) Regulator
VIN (V) (min) 4.5
VIN (V) (max) 40
VOUT1 (V) (min) 1.23
VOUT1 (V) (max) 100
IOUT1 (A) (max) 10
Switch Type External
VOUT1 Tolerance (±%) 1
Output Adjust. Method Resistor
Power Good Signal Yes
ICC (mA) (max) 3.1
# DC-DC Outputs 1
Alternate Topology Inverting
Step-Up
Switching Frequency (kHz) 1000
Package/Pins TSSOP/16
Oper. Temp. (°C) -40 to +125
Budgetary
Price (See Notes)
$1.57 @1k

Key Features

  • Wide Supply Voltage Range Meets Automotive Power-Supply Operating Requirement Including "Cold Crank" Conditions
    • 4.5V to 40V Operating Input Voltage Range (Can Operate at Lower Voltage After Startup if Input is Bootstrapped to a Boosted Output)
  • Control Architecture Offers Excellent Performance While Simplifying the Design
    • Current-Mode Control
    • 300mV, 5% Accurate Current-Limit Threshold Voltage
    • Programmable Slope Compensation
    • 50% (MAX15004) or Adjustable (MAX15005) Maximum Duty Cycle
  • Accurate, Adjustable Switching Frequency and Synchronization Avoids Interference with Sensitive Radio Bands
    • Switching Frequency Adjustable from 15kHz to 500kHz (1MHz for the MAX15005A/B/C/D)
    • RC Programmable 4% Accurate Switching Frequency
    • External Frequency Synchronization
  • Built-In Protection Capability for Improved System Reliability
    • Cycle-by-Cycle and Hiccup Current-Limit Protection
    • Overvoltage and Thermal-Shutdown Protection
    • -40°C to +125°C Automotive Temperature Range
    • AEC-Q100 Qualified

Applications/Uses

  • Automotive
  • Isolated Flyback, Forward, Nonisolated SEPIC, Boost Converters
  • Vacuum Fluorescent Display (VFD) Power Supply

Description

The MAX15004/MAX15005 high-performance, current-mode PWM controllers operate at an automotive input voltage range from 4.5V to 40V (load dump). The input voltage can go lower than 4.5V after startup if IN is bootstrapped to a boosted output voltage. The controllers integrate all the building blocks necessary for implementing fixed-frequency isolated/nonisolated power supplies. The general-purpose boost, flyback, forward, and SEPIC converters can be designed with ease around the MAX15004/MAX15005.

The current-mode control architecture offers excellent line-transient response and cycle-by-cycle current limit while simplifying the frequency compensation. Programmable slope compensation simplifies the design further. A fast 60ns current-limit response time, low 300mV current-limit threshold makes the controllers suitable for high-efficiency, high-frequency DC-DC converters. The devices include an internal error amplifier and 1% accurate reference to facilitate the primary-side regulated, single-ended flyback converter or nonisolated converters.

An external resistor and capacitor network programs the switching frequency from 15kHz to 500kHz (1MHz for the MAX15005). The MAX15004A/MAX15005 provide a SYNC input for synchronization to an external clock. The maximum FET-driver duty cycle for the MAX15004A/B/C/D is 50%. The maximum duty cycle can be set on the MAX15005A/B/C/D by selecting the right combination of RT and CT.

The input undervoltage lockout (ON/active-low OFF) programs the input-supply startup voltage and can be used to shutdown the converter to reduce the total shutdown current down to 10µA. Protection features include cycle-by-cycle and hiccup current limit, output overvoltage protection, and thermal shutdown.

The MAX15004/MAX15005 are available in space-saving 16-pin TSSOP and thermally enhanced 16-pin TSSOP-EP packages. All devices operate over the -40°C to +125°C automotive temperature range.

Simplified Block Diagram

MAX15004, MAX15005: Functional Diagram MAX15004, MAX15005: Functional Diagram Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal.