Over the years, Microdul AG has gained experience in the field of medical applications, in particular neuromuscular stimulation. Some ASIC concepts for neurostimulation ASICs that can be implemented in different technologies are presented below.
The low voltage chip MS1031 is realized on Microdul's semicustom array MD500 and offers the possibility of monophasic and biphasic stimulation pulses in bipolar mode for voltages up to 8V. The amplitude of the pulses can be programmed up to 2.55mA with a resolution of 10µA. The programmable time sequences are realized with an internal or external oscillator of 100kHz.
The high voltage chip MS1032 can generate monophasic and biphasic stimulation pulses in monopolar mode for voltages up to 18V. Charge balancing can be realized with or without slow reversal (4:1). The amplitude of the pulses can be programmed up to 2.55mA with a resolution of 10uA. The programmable time sequences are realized with an internal or external oscillator of 100kHz. Overcurrent and undercurrent protection is part of the safety concept. The chip offers a switch matrix where the current sink/source channels and analog peripheral inputs can be flexibly assigned to the outputs of the switch matrix.
MS1033 is a high-voltage ASIC that can generate monopolar and bipolar therapies. It can perform monophasic, biphasic and even DC stimulation. The MS1033 can work with voltages up to 22V. It contains almost all the features of MS1032 and even more. The user can operate multiple MS1033 chips synchronously. An internal charge pump can be used to generate the high-voltage necessary for excitation. The MS1033 offers the option of grouping channels in parallel to drive up to 16x the stimulation current on one channel. Furthermore, the MS1033 provides the possibility to check whether the interface between electrode and tissue is within limits by using its own proprietary impedance check function.
Feature Overview
|
Type |
MS1031 |
MS1032 |
MS1033 |
|
Main feature |
8-channel programmable current pulse generator |
8-channel current sink/source for neuromuscular stimulation |
16-channel current sink/source for neuromuscular stimulation |
|
Pulse modes |
Monophasic |
Monophasic |
Monophasic |
|
Pulse polarity |
Anodic + Cathodic |
Anodic + Cathodic |
Anodic + Cathodic |
|
Stimulation types |
Bipolar |
Monopolar |
Bipolar + Monopolar |
|
Programmable pulse parameters |
Sequence timing and amplitude |
Sequence timing and amplitude |
Sequence timing and amplitude |
|
Max. stimulation Current |
2.55mA |
2.55mA |
2.55mA |
|
Programming resolution of the current |
10uA |
10uA |
10uA |
|
Max. stimulation Voltage |
8V |
18V |
22V |
|
Internal Charge Pump |
No |
No |
Yes |
|
Current sink to source amplitude ratio |
1:1 |
1:1 |
1:1 |
|
Output switch matrix |
No |
Yes |
No |
|
Impedance check |
No |
No |
Yes |
|
Overcurrent and undercurrent protection |
No |
Yes |
No |
|
Internal oscillator |
Yes |
Yes |
Yes |
|
External clock input |
Yes |
Yes |
Yes |
|
Voltage reference |
1.25V internal or external |
1.25V internal or external |
Internal |
|
Shutdown input (safety feature) |
Yes |
Yes |
Yes |
|
Cascading |
Yes |
No |
Yes |
|
10 MHz SPI interface |
Yes |
Yes |
Yes |
|
Operating voltage range |
2.2V…3.3V |
1.8V…4.5V |
3.0V (±10%) |
|
Operating temperature range |
+10°C…+50°C |
+10°C…+50°C |
0°C…+50°C |
|
Packaging |
Various packaging options |
Various packaging options |
QFN56 (7x7) |
|
Concept datasheet |