Abstract
In this work, we present a novel ultralow-power ambient light sensor for distributed sensor node application. The sensor features a minimum supply voltage (<1V) for meeting the low power requirement by a successive approximation register logic combined with progressive sizing current mirrors for analog-to-digital conversion (ADC). The current-mode operation simplifies the ADC circuit design by eliminating the capacitor array, which enables low power consumption. Furthermore, an adjustable dynamic range for indoor or outdoor sensing can be obtained by clock frequency control. This current mode sensor provides a promising solution for distributed environmental sensing modules with tight energy budget. © 2014 The Japan Society of Applied Physics.