GH Crash
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I need help in determining the best approach for a lithium ion capacitor, LIC, (also know as a hybrid capacitor) low-voltage protection circuit. Can you suggest an approach, or a simple circuit design to address the requirement of this circuit?
Background: Hybrid (lithium ion) capacitors have a minimum voltage limit. Discharging them beyond that point, or storing them below their minimum voltage will damage or destroy the capacitor. The circuit (device) needed would be placed between the capacitor and the load and would interrupt the current flow when the capacitor voltage dropped to its minimum allowable voltage. The circuit will be used in environments where size and weight are a major concern.
Circuit requirements
George
Background: Hybrid (lithium ion) capacitors have a minimum voltage limit. Discharging them beyond that point, or storing them below their minimum voltage will damage or destroy the capacitor. The circuit (device) needed would be placed between the capacitor and the load and would interrupt the current flow when the capacitor voltage dropped to its minimum allowable voltage. The circuit will be used in environments where size and weight are a major concern.
Circuit requirements
- The circuit shall not reduce the maximum voltage and/or amperage available at the load.
- The circuit must be capable of handling currents up to 3 amps.
- The circuit should operate satisfactorily at input voltages between one and six volts DC.
- The completed circuit board needs to be small, preferably under 15mm by 15mm square.
- The completed circuit must be light, Under 0.75 grams max weight, under 0.5gshould be the goal.
- Items, or conditions, not directly mentioned in the requirements are left up to the designer's discretion.
- The LIC typically used will be between 10F and 100F capacitance and 5.0 max volts.
- The load will typically be a DC coreless motor of under ten watts and 3.7 volts.
- It is desirable that there be absolutely no current flow once the LIC reaches its minimum voltage limit but quiescent current flow through circuit components may be unavoidable.
George