Product Guides and Tutorials
Power Pulse Modulators
[PWM-OCB, PWM-OCBI, PWM-OCX, PWM-OCXI]
Troubleshooting
Our range of Power Pulse Modulators have been designed to be as versatile and tolerant as possible so that they can be used in all sorts of ways. However, if for some reason your Power Pulse Modulator has been damaged or is malfunctioning, this guide will help you to determine the cause and give you steps to remedy the problem.
Overheating or blown TVS (SP1)
Cause - This component is used to protect the rest of the circuit from large voltage transients. This component will overheat if there are continuous large voltage transients that are above the secondary switching voltage rating of the power pulse modulator.
Solution - You will need to take measures to reduce the transients. This may be as simple as adjusting the frequency. For other methods, please see the page about driving inductive loads. If the component marked SP1 has been damaged, it should be replaced with another TVS. For the PWM-OCB, and PWM-OCX, use the 1.5KE56CA, for the PWM-OCBI and PWM-OCXI, use the 1.5KE440CA
Overheating or blown diode (D1 or D2)
Cause - If you mistakenly connect the power to your device with the wrong polarity and have not used a suitable fuse, either of these diodes could fail. Large transients on the power supply input, or an input supply above the rated value could also lead to overheating of these components.
Solution - Replace the diodes if needed, and ensure you follow all suggestions in the datasheet for operating the device within its defined parameters. D1 is a 1N5363B, and D2 is a 1N5819.
Overheating power capacitor (C2)
Cause - The power supply or connecting cables used have a high impedance and can not deliver fast current pulses to the device.
Solution - Add more capacitance to the input terminals V+ and GND as shown in the datasheet. Use shorter, and thicker cables to connect between the PSU and the Power Pulse Modulator. See the page on power supply considerations for more details.
Overheating or blown power transistor (T1)
Cause - Too much current for the selected frequency.
Solution - Reduce the duty and/or frequency setting. Increase the load impedance. If you need to replace the transistor, for the OCB and OCX use a STP30NF10, or for the OCBI and OCXI use a IRGB4061DPBF