WCD pacing pulse generation

An apparatus, including circuitry comprising:

• an energy storage module;
• a charger, configured to be coupled to a battery and provide a charge to the energy storage module,
• an output circuit block, operatively coupled to the charger and the energy storage module, the output circuit block having at least one output configured to be coupled to first and second therapy electrodes;
• a processor block, operatively couple to the charger, the energy storage module, and the output circuit block, the processor block including one or more processing elements on which instructions are executed and at least one memory in which the instructions are stored;
• and
• one or more software modules comprising the instructions configured to be executed by at least one of the one or more processing elements to enable the apparatus that includes the circuitry to emulate a current source with an adjustable current level to generate pacing pulses delivered to the first and second therapy electrodes, wherein the apparatus is further configured to:
• initiate generation of pacing pulses having a voltage level;
• measure an impedance load of an ambulatory patient;
• and
• adjust the voltage level of the pacing pulses using the measured impedance load.

A method implemented by a wearable cardioverter defibrillator (WCD) worn by an ambulatory patient, the WCD including a battery coupled to WCD circuitry including a charger, an energy storage module, control circuitry, and output circuitry coupled to first and second therapy electrodes in contact with the ambulatory patient, the method comprising:

• controlling the charger with the control circuitry to emulate a current source;
• outputting pacing pulses to the first and second therapy electrodes without the current source;
• initiating generation of pacing pulses having a voltage level;
• measuring an impedance load of the ambulatory patient;
• and
• adjusting the voltage level of the pacing pulses using the measured impedance load.