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Synchronous Boost and Synchronous Buck LED Controllers

Automotive Synchronous Boost Controller with Buck LED Controller Optimizes 2 Stage LED Lighting Designs

Product Details

The MAX25601A/B/C/D is a synchronous boost controller followed by a synchronous buck LED controller. The 4.5V to 40V input voltage range of the boost controller is ideal for automotive applications, and acts as a pre-boost power supply for the second-stage buck LED controller.

The synchronous boost is a current-mode controller that can be be paralleled with another device to provide higher output power. A SYNCOUT pin provides the clock to drive the RT/SYNCIN pin of the other device, enabling two-phase 180-degree out-of-phase operation. The boost converter can be programmed with a switching frequency of 200kHz to 2.2MHz. Spread spectrum is included to reduce EMI. An internal digital soft-start feature is provided to enable a smooth power up of the boost output. Protection features like hiccup mode, overvoltage protection, and thermal shutdown are provided.

The synchronous buck LED controller uses Maxim's F3 Architecture, a proprietary average-current-mode control scheme to regulate the inductor current at a constant switching frequency without any control-loop compensation. Inductor current is sensed in the bottom synchronous n-channel MOSFET. The device operates over a wide 4.5V to 65V input range at switching frequencies as high as 1MHz. Both analog and PWM dimming are included. LED current can be monitored on the IOUTV pin.

Both controllers have high- and low-side gate drivers with at least 1A peak source and sink-current capability. Adaptive non-overlap control logic prevents shoot-through currents during transition. Both the boost and the buck faults are monitored on the active-low FLT pin.

The MAX25601A/C is available in a 32-pin SWTQFN package and the MAX25601B/D is available in a 28-pin TSSOP package. The 32-pin package features an additional switch control that can be used in high-beam/low-beam and heads-up display applications.

Key Features

  • Integration Minimizes BOM for High-Brightness LED Driver, Saving Space and Cost
    • Wide Input-Voltage Range from 4.5V to 40V
    • Wide Boost-Output Range up to 65V
    • Programmable Switching Frequency Optimizes Component Size
    • External MOSFETs Can be Sized for Appropriate Current
    • Synchronous Rectification Provides High Efficiency and Fast Transient Response
    • Average Current-Mode Control for Buck Eliminates Compensation Components
  • Wide Dimming Ratio Allows High Contrast Ratio
    • Analog Dimming and PWM Dimming
    • Analog Voltage-Controlled PWM Dimming
  • Protection Features and Wide Temperature Range Increase System Reliability
    • Short Circuit, Overvoltage, and Thermal Protection
    • -40°C to +125°C Operating Temperature Range

Applications/Uses

  • Automotive Exterior Lighting: High-Beam/Low-Beam/ Signal/Position Lights, Daytime Running Lights (DRLs), Matrix Light, Pixel Light, and Other Adaptive Front-Light Assemblies
  • Commercial, Industrial, and Architectural Lighting
Parametric specs for LED Drivers
VIN (V) (min) 4.5
VIN (V) (max) 48
Max. No. of LEDs 15
# LED Channels 1
Regulation Topology Inductor Based
LED Configuration -
ILED per Channel (A) (max) 30
PWM Dimming Freq. (kHz) (max) 2
Dimming Ratio (max) 10000
Dimming Control Analog
Analog Controlled PWM
PWM
VCURR_SENSE (mV) 200
POUT (W) 100
ICC (mA) (max) -
LED String Volt. (V) (max) 60
Switching Frequency (kHz) 1000
Package/Pins TQFN-CU/32
Budgetary
Price (See Notes)
$2.71 @1k
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Simplified Block Diagram

MAX25601A, MAX25601B, MAX25601C, MAX25601D: Simplified Application Circuit MAX25601A, MAX25601B, MAX25601C, MAX25601D: Simplified Application Circuit Zoom icon

Technical Docs

Design & Development

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Description

The MAX25601 evaluation kit (EV kit) provides a proven design to evaluate the MAX25601A/MAX25601C automotive high-voltage, high-brightness LED (HB LED) boost-buck controller. The front-end pre-boost operates from a 7.7V to 18V DC supply voltage, generating a 48V output. The buck supports 12x LEDs and lower, delivering up to 1.5A to one string of LEDs. The total voltage of the string can vary from 3V to 36V.

View Details

Features

  • Configured for Pre-Boost and Buck Application
  • Analog Dimming Control
  • Proven PCB Layout
  • Fully Assembled and Tested

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Parameters

Parametric specs for LED Drivers
VIN (V) (min) 4.5
VIN (V) (max) 48
Max. No. of LEDs 15
# LED Channels 1
Regulation Topology Inductor Based
LED Configuration -
ILED per Channel (A) (max) 30
PWM Dimming Freq. (kHz) (max) 2
Dimming Ratio (max) 10000
Dimming Control Analog
Analog Controlled PWM
PWM
VCURR_SENSE (mV) 200
POUT (W) 100
ICC (mA) (max) -
LED String Volt. (V) (max) 60
Switching Frequency (kHz) 1000
Package/Pins TQFN-CU/32
Budgetary
Price (See Notes)
$2.71 @1k

Key Features

  • Integration Minimizes BOM for High-Brightness LED Driver, Saving Space and Cost
    • Wide Input-Voltage Range from 4.5V to 40V
    • Wide Boost-Output Range up to 65V
    • Programmable Switching Frequency Optimizes Component Size
    • External MOSFETs Can be Sized for Appropriate Current
    • Synchronous Rectification Provides High Efficiency and Fast Transient Response
    • Average Current-Mode Control for Buck Eliminates Compensation Components
  • Wide Dimming Ratio Allows High Contrast Ratio
    • Analog Dimming and PWM Dimming
    • Analog Voltage-Controlled PWM Dimming
  • Protection Features and Wide Temperature Range Increase System Reliability
    • Short Circuit, Overvoltage, and Thermal Protection
    • -40°C to +125°C Operating Temperature Range

Applications/Uses

  • Automotive Exterior Lighting: High-Beam/Low-Beam/ Signal/Position Lights, Daytime Running Lights (DRLs), Matrix Light, Pixel Light, and Other Adaptive Front-Light Assemblies
  • Commercial, Industrial, and Architectural Lighting

Description

The MAX25601A/B/C/D is a synchronous boost controller followed by a synchronous buck LED controller. The 4.5V to 40V input voltage range of the boost controller is ideal for automotive applications, and acts as a pre-boost power supply for the second-stage buck LED controller.

The synchronous boost is a current-mode controller that can be be paralleled with another device to provide higher output power. A SYNCOUT pin provides the clock to drive the RT/SYNCIN pin of the other device, enabling two-phase 180-degree out-of-phase operation. The boost converter can be programmed with a switching frequency of 200kHz to 2.2MHz. Spread spectrum is included to reduce EMI. An internal digital soft-start feature is provided to enable a smooth power up of the boost output. Protection features like hiccup mode, overvoltage protection, and thermal shutdown are provided.

The synchronous buck LED controller uses Maxim's F3 Architecture, a proprietary average-current-mode control scheme to regulate the inductor current at a constant switching frequency without any control-loop compensation. Inductor current is sensed in the bottom synchronous n-channel MOSFET. The device operates over a wide 4.5V to 65V input range at switching frequencies as high as 1MHz. Both analog and PWM dimming are included. LED current can be monitored on the IOUTV pin.

Both controllers have high- and low-side gate drivers with at least 1A peak source and sink-current capability. Adaptive non-overlap control logic prevents shoot-through currents during transition. Both the boost and the buck faults are monitored on the active-low FLT pin.

The MAX25601A/C is available in a 32-pin SWTQFN package and the MAX25601B/D is available in a 28-pin TSSOP package. The 32-pin package features an additional switch control that can be used in high-beam/low-beam and heads-up display applications.

Simplified Block Diagram

MAX25601A, MAX25601B, MAX25601C, MAX25601D: Simplified Application Circuit MAX25601A, MAX25601B, MAX25601C, MAX25601D: Simplified Application Circuit 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