178002 Wurth

Reference Design Note 3 MagI C Power Modules 3 DNS002 MagI C Power Supply 1. Introduction 3 3 The MagI C Power Supply demonstrates how a MagI C Power Module can be used for applications that require additional power supply functionalities. An adjustable output current limit can be set from 0mA to the maximum continuous output current of the module, turning the module into a constant current source or still acting as a voltage source but with a user defined current limit. An electronic fuse can be implemented by triggering on the current limit LED and pulling the enable pin low to shut down 3 the MagI C Power Module immediately after a current limit event. Output voltage and current can have arbitrary waveforms. An example is imitating the behavior of a car battery voltage during engine start up to test if the radio is malfunctioning. Batteries can be charged with a DC current or with a defined charging current waveform, if a digital to analog converter or a PWM output of a microcontroller is used instead of the potentiometer for current adjustment. Other possibilities include end of charge voltage as well as super capacitor charging. High power LEDs can be supplied up to 2.5A. 3 The point of regulation can be moved away from the MagI C Power Module towards the load. This allows regulation of the voltage at a distant point while the output voltage of the module adapts to the voltage drops on the supply lines. 3 During the development of a customers prototype, the MagI C Power Supply can be implemented into the prototypes housing until the power supply is defined for the final product. 3 Figure 1. MagI C Power Supply Order Code 178002 DNS002 V2.0 Roland Kratz - December 2018 Page 1/8 Copyright Wrth Elektronik eiSos GmbH & Co. KGReference Design Note 3 MagI C Power Modules 3 DNS002 MagI C Power Supply 2. Specifications Electrical Specifications Features Input Voltage Range 7V 36V Output On/Off Mechanical Switch Input Voltage Transients Max. 45V Constant Voltage Indicator LED green Output Voltage Range 0V 15V Constant Current Indicator LED red Output Current Limit 0A 2.5A Output Fail Indicator LED red Maximum Output Power 37.5W Switching Frequency 1MHz 3. Functional Diagram Power Module L 1 T 1 V V IN OUT T2 C R C Controller IC OUT LOAD IN R s Error Amplifier Adj. Current Set Value R 1 Error Amplifier R 2 Adj. Voltage Set Value Figure 2. Functional Diagram 3 The output voltage of the MagI C Power Module, normally fixed by the feedback resistor divider R and R , is now adjustable 1 2 3 during operation by one of the error amplifiers. It can even be regulated below the internal reference of the MagI C Power Module down to 0V while continuing to be actively regulated. The output current is measured by RS and compared with an internal reference by the second error amplifier. Either the error amplifier for voltage regulation is active and maintains the output voltage according to the user set value or the error amplifier for current regulation is active and maintains the output current according to the user set value. DNS002 V2.0 Roland Kratz - December 2018 Page 2/8 Copyright Wrth Elektronik eiSos GmbH & Co. KG Feedback