Speed-Power Improvement in High-Voltage Switches Employed in Multielectrode Arrays

In multi-electrode arrays (MEAs), for electrical recording and electrical stimulation, high voltage (HV) switches are employed to build an analog multiplexer to conduct either a HV stimulation signal from the pulse generator circuit to an electrode or a low-voltage noise-sensitive signal from the electrode to a recording stage. In this brief, a new circuit structure is proposed for HV switches that significantly improves their switching speed, reduces their power dissipation, and also employs a minimum number of bulky HV devices. In order to reduce the transition time of the proposed switch without consuming a large amount of power, during the transition time that the switch is turning on/off, a large current flows through the driver circuit of the switch to turn the switch on/off rapidly; however, after the transition times, this current is significantly reduced to save power. Based on the proposed HV switch, a multiplexer structure has been implemented in 25-V, 0.18-
$\mu \text{m}$
CMOS IC technology and the measurement results prove its efficacy. Supplied with 25 V and operating with 300 nA current consumption, this switch swings over 20 V with a relatively constant on-resistance of
$100 \Omega $
and features a 80 ns transition time.