zoulzubazz
Member level 5
hey guys,
the requirement is to design a dual constant current stimulator (1mA through 3kohm max. load), which are isolated from each other. the right side of the attachment shows the output required from this circuit. its a bipolar square wave at 2Hz with 50% duty cycle. the following description is for a system i think might work but need your suggestions for errors and improvement.
since the required output is bipolar the choice is a howland current pump (see link for circuit)which can both source and sink current, shown as How1 and How2 in the attachment. is this the right choice are there any simpler alternatives?
now to feed the two howland circuits with a bipolar input voltage, this is the plan. the system this unit will work with has a few spare gpio pins from a microcontroller which will turn on and off two transistor switches (TrSW1 and TrSW2 in attachment) connected to the supply. When a particular switch turns on the supply voltage (or a portion of it) will be fed to the input of the howland circuit with the other input referenced to a portion of the negative supply, this will give a bipolar output current (hopefully). is there a more efficient way of achieving the same result because i have a feeling i am going down a long route.
the plan is to use two button cell batteries to power the each stimulator. regarding the isolation of the two simulators are there any ic packages which can turn a single dual-supply to two dual-supplies?
Also any comment on the power consumption of the envisaged stimulator?
any other problems or comments?
https://www.indiabix.com/electronics-circuits/howland-current-source/
thanks very much
the requirement is to design a dual constant current stimulator (1mA through 3kohm max. load), which are isolated from each other. the right side of the attachment shows the output required from this circuit. its a bipolar square wave at 2Hz with 50% duty cycle. the following description is for a system i think might work but need your suggestions for errors and improvement.
since the required output is bipolar the choice is a howland current pump (see link for circuit)which can both source and sink current, shown as How1 and How2 in the attachment. is this the right choice are there any simpler alternatives?
now to feed the two howland circuits with a bipolar input voltage, this is the plan. the system this unit will work with has a few spare gpio pins from a microcontroller which will turn on and off two transistor switches (TrSW1 and TrSW2 in attachment) connected to the supply. When a particular switch turns on the supply voltage (or a portion of it) will be fed to the input of the howland circuit with the other input referenced to a portion of the negative supply, this will give a bipolar output current (hopefully). is there a more efficient way of achieving the same result because i have a feeling i am going down a long route.
the plan is to use two button cell batteries to power the each stimulator. regarding the isolation of the two simulators are there any ic packages which can turn a single dual-supply to two dual-supplies?
Also any comment on the power consumption of the envisaged stimulator?
any other problems or comments?
https://www.indiabix.com/electronics-circuits/howland-current-source/
thanks very much