MPQ2908 - 48V Buck Converter for Automotive Systems

REFERENCE DESIGN

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Description

New automotive designs are adopting 48V power systems in order to reduce power loss in the vehicle’s cable harnesses and reduce their weight. However, this presents a challenge when trying to comply with EMC regulations. Success is possible through thoughtful component placement and PCB layout, together with techniques like frequency spread-spectrum (FSS).

This reference design showcases a 48V to 12V buck converter, capable of delivering 15A of current and complying with CISPR-25 Class 5 EMC standard.

AEC-Q100 Qualified
Wide 4V to 60V Operating Input Range
Dual N-Channel MOSFET Driver
0.8V Voltage Reference with ±1.5% Accuracy Over Temperature
Low Dropout Operation: Maximum Duty Cycle at 99.5%
Programmable Frequency Range: 100kHz - 1000kHz
External Sync Clock Range: 100kHz - 1000kHz
180º Out-of-Phase SYNCO Pin
Programmable Soft Start (SS)
Power Good (PG) Output Voltage Monitor
Selectable Cycle-by-Cycle Current Limit
Output Over-Voltage Protection (OVP)
Over-Current Protection (OCP)
Internal LDO with External Power Supply Option
Programmable Forced CCM and AAM
Available in TSSOP20-EP and QFN-20 (3mmx4mm) Packages
Available in a Wettable Flank Package
External Frequency Spread-Spectrum modulation (FSS)
External Input Over-Voltage Protection (OVP)
External Reverse-Polarity Protection (RPP)

1.2 Applications

Automotive Power Systems
Industrial Systems

1.3 Block Diagram

Buck converter with 48V nominal input, 12V 15A output capability, input EMI filter, RPP and OVP, FSS modulation.

Figure 1: Block Diagram

1.4 Related Solutions

MPS Integrated Circuit	Description
MPQ2908A	4V-60V Input, Current Mode, Synchronous, Step-Down Controller. AEC-Q100 Qualified

Table 1: MPS Solutions

1.5 System Specifications

Parameter	Specification
Input voltage range	18VDC to 60VDC
Output voltage	12VDC
Maximum output current	15A (with 12V output)
Switching frequency	430kHz
Board form factor	94mmx78mmx12mm
Peak efficiency	94.2%
12V output ripple	22mV_p-p