Comparison of V2IC control with voltage mode and current mode controls for high frequency (MHz) and very fast response applications

High switching frequencies (several MHz) allow the integration of low power DC/DC converters. Although, in theory, a high switching frequency would make possible to implement a conventional Voltage Mode control (VMC) or Peak Current Mode control (PCMC) with very high bandwidth, in practice, parasitic effects and robustness limits the applicability of these control techniques. This paper compares VMC and CMC techniques with the V2IC control. This control is based on two loops. The fast internal loop has information of the output capacitor current and the error voltage, providing fast dynamic response under load and voltage reference steps, while the slow external voltage loop provides accurate steady state regulation. This paper shows the fast dynamic response of the V2IC control under load and output voltage reference steps and its robustness operating with additional output capacitors added by the customer.

Temperature controlled light-emitting diode lamp for photovoltaic rural applications

In recent years, interest in light-emitting diode (LED) lighting has been growing because of its high efficacy, lifetime and ruggedness. This paper proposes a better adaptation of LED lamps to the technical requirements of photovoltaic lighting domestic systems, whose main quality criteria are reliability and that behave as voltage power supplies. As the key element of reliability in LED lamps is temperature, a solution is proposed for driving LED lamps using voltage sources, such as photovoltaic system batteries, with a control architecture based on pulse width modulation signal that regulates the current applied according to the LED lamp temperature. A prototype of the LED lamp has been implemented and tested to show its good performance at different temperatures and at different battery voltages.