POWER AND LINEAR IC SOLUTIONS

DC-DC Controller Provides High Efficiencies for Automotive Applications

Intended primarily for use in automotive applications, the TLE6389 step-down DC-DC controller from Infineon is designed to accommodate high input voltage range requirements, whilst providing high efficiency under variable load conditions.

A proprietary peak current-limited, PWM/PFM control scheme gives these devices excellent efficiency over wide load ranges (1mA to 3A), while reducing current draw under light load to around 100µA. It is these characteristics that suit the device for use in automotive environments, where load currents can vary considerably as individual circuit blocks are turned on and off to conserve energy.



Operation to a 100% duty cycle allows the lowest possible dropout voltage, maintaining operation during cold cranking. High (350kHz) switching frequencies and a simple circuit topology minimise PC board area and component costs.

Output voltage is preset at 5V (TLE6389G50-1 and TLE6389G50 versions) and is adjustable for the TLE6389GV. Input voltages can be up to 60V. The controllers drive a high-efficiency external P-channel MOSFET, allowing design flexibility for applications requiring up to 15W of output power. Their high switching frequency and operation in continuous-conduction mode allow the use of tiny surface-mount inductors. Output capacitor requirements are also reduced, minimising PC board area and system costs.



Emerging 42V Powernet and existing automotive body electronics functions bring strict requirements in terms of converter current consumption. The TLE6389 meets these by implementing a control strategy that combines PFM (Pulse Frequency Modulation) and PWM (Pulse Width Modulation). This uses the load current to determine PFM frequency to be used with lighter loads, before turning to fixed-frequency PWM control at a point defined by the input voltage, current sense resistor and inductance.

Features

• 15W automotive step-down regulator
• Input voltage range from less than 5V up to 60V
• 5V fixed and adjustable output versions
• Output voltage accuracy: 3%
• Load current peak determined by external sense resistor
• 100% maximum duty cycle
• Less than 100µA quiescent current at low loads
• 2µA maximum shutdown current at device off
• Fixed 350kHz PWM switching frequency
• Frequency synchronisation input for external clocks
• Current mode control scheme
• Integrated output undervoltage reset circuit
• On-chip low battery detector
• Automotive temperature range
• SO14 package

For further information, including the TLE6389 Datasheet and the DC-DC Selection Guide, please click here.