Speakers
Description
Cadmium Zinc Telluride (CdZnTe) detectors are widely used in high-energy physics, space detection, and nuclear medical imaging, due to their high energy resolution for gamma rays and operating in room temperature. In order to supply clean power to a 32-channel front-end readout circuit for CdZnTe detectors, a fully integrated low dropout (LDO) voltage regulator is proposed in this paper.
Since output pole varies with the load current and external frequency compensating components are not allowed, it is difficult to keep LDO stable. In order to address this problem, a novel frequency compensation method based on load-current partition is proposed. The topology of compensation circuit can be adjusted by sensing the load current. Thus, the compensating zero can well track the output pole in the full range of load current without sacrificing loop-gain bandwidth or increasing die area. Moreover, feedforward ripple cancellation is introduced to enhance the power supply rejection (PSR).
The proposed LDO has been designed and fabricated in 0.18 μm CMOS Technology, occuping an area of 120×264 μm2. Simulation results show that the phase margin is greater than 53° at the load capacitance of 200 nF and the load current ranging from 0 to 200 mA. Measured load regulation and line regulation are 77 mV/A and 4.09 mV/V, respectively. Measured PSR is -21 dB at 1 MHz. The maximum power efficiency is 97.8% and the minimum dropout voltage is 70 mV. For a 150 mA load current step, the transient response time is less than 5.5 μs.
| Minioral | Yes |
|---|---|
| IEEE Member | No |
| Are you a student? | Yes |