Contents

• Abstract
• INTRODUCTION AND BACKGROUND
• METHODOLOGY
• ANALYSIS
• CONCLUSION
• References

Description

The UCC3750 is ring controller used to provide the complete drive solution for a four quadrant fly back based ring generator circuit. The controller drives the switches working on the principal of pulse width modulation. The IC controls the primary side switch which is modulated when power is transferred from input to output and two secondary side switches which functions as synchronous rectifier switches during positive power transfer. The application circuit specified by the manufacturer uses the topology of four quadrant fly back converter aiming to generate 86VAC sinusoidal from the input of 48VDC with onboard programmable frequencies of 20Hz, 25Hz or 50 Hz. The output frequencies are generated by onboard sine wave reference which is derived by 32 KHz crystal externally. The IC also sense the output voltage with the help of feedback loop and on application of load, it tends to regulate the output voltage by changing the duty cycle of switches. The circuit is redesigned to generate the 90VAC sinusoidal from the input of 14.4VDC at the load of one telephone ringer by changing a few components and adjusting feedback loop parameters. So in this paper, experimentation and optimization of ring generator circuit is done to achieve the output voltage regulation at the changing window of input voltage from 12VDC to 16VDC at the load of one ringer circuit. Load regulation is also optimized to maintain above 60VAC on the application of load up to 8REN (Ringer Equivalent Number). Here 1REN represent one telephone ringer which is equivalent to the load of 20KΩ.