DEMO MANUAL DC2337A LT8315 Offline Isolated Flyback Converter Description Demonstration circuit 2337A is an offline isolated flyback operation improves load regulation, reduces transformer converter featuring LT 8315. The demo board outputs 12V, size, and maintains high efficiency. The LT8315 is available and maintains tight regulation with a load current from in a thermally enhanced 20-pin TSSOP package with four 4mA to 0.55A. It is optimized to operate over a wide AC pins removed for high voltage spacing. input voltage range (90VAC to 265VAC, 47Hz to 63Hz). The LT8315 data sheet gives a complete description of Output voltage accuracy stays within 5% over the whole the part, operation and application information. The data input voltage and load range. sheet must be read in conjunction with this quick start The LT8315 is a high voltage flyback converter with inte- guide for demo circuit 2337A. grated 630V/300mA switch. No opto-isolator is needed for Design files for this circuit board are available at regulation. The part samples the output voltage from the DEMO MANUAL DC2337A Quick s tart p D IMPORTANT NOTE TO CUSTOMERS: NOTE: Make sure that the input voltage is always within spec. To operate the board with higher input/output HIGH VOLTAGES ARE PRESENTED ON THE DEMO CIRCUIT, voltage, input capacitor, output capacitor and output AND CAN LEAD TO LETHAL INJURIES TO HUMAN BODY. diode with higher voltage ratings are needed. ONLY QUALIFIED PERSONNEL SHOULD OPERATE IT. IT IS STRONGLY RECOMMENDED TO USE SAFETY GLASSES 3. Check for the proper output voltages. The output should AND AN ISOLATION TRANSFORMER. be regulated at 12V (5%). NOTE. IMPROPER COMPONENTS REPLACEMENT ON THE NOTE: The LT8315 requires very small minimum load DEMO CIRCUIT CAN CAUSE PERFORMANCE DETERIORA- to maintain good output voltage regulation. A Zener TIONS, CIRCUIT MALFUNCTION, PROPERTY DAMAGE, diode is placed on the output to clamp the voltage to AND EVEN LIFE-THREATENING INJURIES. CONTACT 13V. This Zener can be replaced with a 3000 resistor LINEAR TECHNOLOGY APPLICATIONS ENGINEERS FOR at the trade-off of lower efficiency. PROPER COMPONENT REPLACEMENT. 4. Once the proper output voltage is established, adjust Demonstration circuit 2337A is easy to set up to evalu- the input voltage and load current within the operating ate the performance of the LT8315. Refer to Figure 1 for range and observe the output voltage regulation, ripple proper measurement equipment setup and follow the voltage, efficiency and other parameters. procedure below: NOTE: When measuring the input or output voltage 1. With power off, connect the AC input power supply to ripples, care must be taken to avoid a long ground lead the board through line and neutral terminals. Connect on the oscilloscope probe. Measure the output voltage + + the load to the terminals V and V on the board. ripple by touching the probe tip directly across the V OUT OUT OUT and V terminals. OUT 2. Turn on the power at the input. Set the input voltage to 120VAC. Figure 1. Proper Measurement Equipment Setup dc2337af 2 ure roce