A 0.90–4.39-V Detection Voltage Range, 56-Level Programmable Voltage Detector Using Fine Voltage-Step Subtraction for Battery Management

A programmable voltage detector (PVD) for battery management is proposed to achieve the programmability of the detection voltage (V
_DETECT
). Thanks to the programmability, users can set an appropriate V
_DETECT
for battery management considering the operating voltage of the battery. For batteries including Li-ion and NiMH batteries, a PVD is required to achieve wide programmed V
_DETECT
range from 1.0 to 4.35 V with a fine voltage step of ±42 mV. Furthermore, the power consumption of the PVD must be minimized since the PVD is always operating in battery management. To achieve both the target programmability of V
_DETECT
and the low power consumption of the PVD, a programmable voltage reference (PVREF) using a fine voltage-step subtraction (FVS) method is proposed. The FVS is a combination of fine and coarse programming for the output of the PVREF, which achieves a fine voltage step and a wide programmable range of V
_DETECT
achieving both a low temperature coefficient of V
_DETECT
and low power consumption of the PVD. The measurement results of the PVD fabricated in a 250-nm CMOS process show a current consumption of the PVD of 1.2 nA at 3.5 V and a temperature coefficient of V
_DETECT
of 0.28 mV/°C. The PVD enables the widest programmable range of V
_DETECT
from 0.90 to 4.39 V, fine V
_DETECT
resolution of ±31.5 mV, and 56-level linear, monotonic programmability of V
_DETECT
.