This paper describes the evaluation of the Voltage Down Converter (VDC) with low ratio of consuming current to load current in DC/AC operation mode. The stability, response and power consumption are investigated. First, for the stability and response, the VDC can operate in the condition that the bounce of the down voltage (dVDL) is no more than 10% of the setting voltage and the maximum load operation frequency (fmax) is 100 MHz at the average load current 70 mA (the maximum load current 140 mA). Secondly, for the power consumption, by using this VDC technology, the value of IC/IL can be suppressed to 5.1E-4 (IC: total consuming current in VDC, IL: average load current) in the condition that dVDL is no more than 10% of the setting voltage and fmax is 10 MHz at the average load current 70 mA. Thus, it is made clear that the VDC can realize high stability, good response and low power consumption at the same time. This technology is suitable for high performance ULSIs which require large load current and low-power consumption.

A high performance voltage down converter (VDC) is proposed in this paper. The proposed VDC can automatically control the driving current in seven phases to reduce the fluctuation of output voltage in VDC. By using above new flexible control technology of driving current, the fluctuation of output voltage can be suppressed to less than 10% and the average consuming current of VDC can be suppressed to 34 µA, even if the operation frequency is 200 MHz at the average driving current 100 mA. Therefore, the proposed VDC can operate with large driving current, low-power consumption and good response at the same time. Above all, this technology is very suitable for high perform ULSIs which require large load current, very low-power and high speed operation.