A circuit includes first and second power nodes having differing first and second voltage levels, and a reference node having a reference voltage level. A master latch outputs a first data bit based on a received data bit; a slave latch includes a first inverter that outputs a second data bit based on the first data bit and a second inverter that outputs an output data bit based on a selected one of the first data bit or a third data bit; a level shifter outputs the third data bit based on a fourth data bit; and a retention latch outputs the fourth data bit based on the second data bit. The first and second inverters and the level shifter are coupled between the first power node and the reference node, and the retention latch includes a plurality of transistors coupled between the second power node and the reference node.

A circuit includes first and second power nodes having differing first and second voltage levels, and a reference node having a reference voltage level. A master latch outputs a first data bit based on a received data bit; a slave latch includes a first inverter that outputs a second data bit based on the first data bit and a second inverter that outputs an output data bit based on a selected one of the first data bit or a third data bit; a level shifter outputs the third data bit based on a fourth data bit; and a retention latch outputs the fourth data bit based on the second data bit. The first and second inverters and the level shifter are coupled between the first power node and the reference node, and the retention latch includes a plurality of transistors coupled between the second power node and the reference node.

Portable high-voltage electrical stimulation devices and systems are disclosed that are scalable to utilize a minimal number of output channels to a large number of output channels. The devices and systems include a high-voltage power supply and output pulse circuitry comprising a plurality of output channel circuits. The electrical stimulation devices and systems disclosed herein also provide improved safety features, including an optional safety monitor.

A voltage driver circuit for an output stage of an operational amplifier, or other circuits, includes a level shifter and an output driver including a source follower and a common source amplifier in a push-pull configuration. The level shifter generates a node voltage as a function of an input voltage on the input node. The output driver including a first transistor having a control terminal receiving the node voltage, and connected between a supply voltage and an output node, and a second transistor having a control terminal receiving the input voltage from the input node, and connected between the output node and a reference voltage, wherein the first and second transistors have a common conductivity type.

A voltage driver circuit for an output stage of an operational amplifier, or other circuits, includes a level shifter and an output driver including a source follower and a common source amplifier in a push-pull configuration. The level shifter generates a node voltage as a function of an input voltage on the input node. The output driver including a first transistor having a control terminal receiving the node voltage, and connected between a supply voltage and an output node, and a second transistor having a control terminal receiving the input voltage from the input node, and connected between the output node and a reference voltage, wherein the first and second transistors have a common conductivity type.

A voltage driver circuit for an output stage of an operational amplifier, or other circuits, includes a level shifter and an output driver including a source follower and a common source amplifier in a push-pull configuration. The level shifter generates a node voltage as a function of an input voltage on the input node. The output driver including a first transistor having a control terminal receiving the node voltage, and connected between a supply voltage and an output node, and a second transistor having a control terminal receiving the input voltage from the input node, and connected between the output node and a reference voltage, wherein the first and second transistors have a common conductivity type.

A voltage driver circuit for an output stage of an operational amplifier, or other circuits, includes a level shifter and an output driver including a source follower and a common source amplifier in a push-pull configuration. The level shifter generates a node voltage as a function of an input voltage on the input node. The output driver including a first transistor having a control terminal receiving the node voltage, and connected between a supply voltage and an output node, and a second transistor having a control terminal receiving the input voltage from the input node, and connected between the output node and a reference voltage, wherein the first and second transistors have a common conductivity type.

Neuromuscular stimulation is widely used for rehabilitation and movement assist devices, due to its safety, efficacy, and ease of operation. For repeatable and accurate muscular contractions, a voltage controlled current sources (VCCS) with high compliance is required. Conventional VCCS design requires high-voltage rated operational amplifiers, which are expensive and consume large power. Moreover, conventional stimulators are not viable for simultaneous stimulation of muscle synergies, as they require multiple VCCS operating at the same time. This invention presents a neuromuscular stimulator with a multistage driver circuit wherein, a VCCS connected to an output driving stage comprising of folded-cascode transistor buffers and a bidirectional current mirror circuit. The multistage driver circuit uses inexpensive low-voltage rated operational amplifiers that consume 95% less power. Additionally, we disclose a stimulation method wherein only a single current source drives several output drivers connected in series or parallel to simultaneously stimulate multiple muscles or muscle synergies.

Neuromuscular stimulation is widely used for rehabilitation and movement assist devices, due to its safety, efficacy, and ease of operation. For repeatable and accurate muscular contractions, a voltage controlled current sources (VCCS) with high compliance is required. Conventional VCCS design requires high-voltage rated operational amplifiers, which are expensive and consume large power. Moreover, conventional stimulators are not viable for simultaneous stimulation of muscle synergies, as they require multiple VCCS operating at the same time. This invention presents a neuromuscular stimulator with a multistage driver circuit wherein, a VCCS connected to an output driving stage comprising of folded-cascode transistor buffers and a bidirectional current mirror circuit. The multistage driver circuit uses inexpensive low-voltage rated operational amplifiers that consume 95% less power. Additionally, we disclose a stimulation method wherein only a single current source drives several output drivers connected in series or parallel to simultaneously stimulate multiple muscles or muscle synergies.

A circuit includes multiple stages cascaded in a ring topology such that each stage has a preceding stage, a succeeding stage, an alternate-preceding stage, and an alternate-succeeding stage. Each stage includes a MOS transistor of a first type, a MOS transistor of a second type and a resistor. The MOS transistor of a first type receives a first input that is output from the preceding stage, and outputs a second output to the alternate-preceding stage. The MOS transistor of a second type receives a second input that is output from the alternate-succeeding stage, and outputs a first output to the succeeding stage. The resistor provides coupling and level-shifting between the first output and the second output.