The active-clamp couple-buck converter-a novel high efficiency voltage regulator modules

Abstract

As the power demand for microprocessors increases steadily, the VRMs are required to work with a higher input voltage. The widely used synchronous buck converter will NOT work properly and efficiently for this higher input voltage because of an extremely small dutyratio. This paper proposes a novel active-clamp couplebuck converter to solve the extremely small duty-ratio problem. Other benefits of the proposed circuit include recovery leakage energy, clamped device voltage and reduced input filter. The proposed circuit was demonstrated on a 4-phase VRM, which delivers power from a 12V input to a 1.5V/50A microprocessor load. Experiments show that the proposed circuit would significantly improve the VRM efficiency.

Ultrahigh Step-Down Converter

“…The condition for the magnetizing inductor L m operating in what region will be described as follows: (19) where Lm I and Lm i Δ are the dc and ac components of i Lm , respectively. The expression of I Lm can be obtained from (20) and (21).…”

“…The method described in [4] possesses the floating output, which limits the applications. The method described in [8][11]- [13][15] [19] [20][27]- [29] possesses nonlinearity in voltage conversion ratio, thereby making the controller design difficult. The method described in [30] needs many inductors, capacitors and diode arrays, leading to too many components used and relatively low efficiency.…”

Improvement in Voltage Conversion Ratio of Ultrahigh Step-Down Converter

“…The circuits shown in [8,9] are improvements of the circuits shown in [7,10]. The literatures [11][12][13][14][15][16] apply central-tapped coupling inductors to synchronously rectified (SR) buck converters so as to obtain relatively high step-down voltage conversion ratios. In the literatures [17][18][19], via changing the turns ratios of coupling inductors, not only the voltage stresses on switches can be reduced but also relatively high step-down voltage conversion ratios can be achieved.…”

Non‐isolated large step‐down voltage conversion ratio converter with non‐pulsating output current

“…On the other hand, the tapped‐inductor buck converter is another popular topology for large step‐down voltage conversion ratio applications due to its simple structure. In , these converters can achieve large step‐down voltage conversion ratio based on tapped inductors. However, the secondary winding of the coupled inductor is connected to the output terminal.…”