Pulse Definition Circuitry for Implantable Stimulators
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Solution Overview
Problem
The existing stimulation circuitry in implantable pulse generators (IPGs) lacks flexibility in defining complex pulses, limiting the ability to create more sophisticated stimulation patterns, and requires extensive register banks and power-consuming flip flops, leading to increased layout area and power consumption.
Innovation Solution
The improved stimulation circuitry employs a microcontroller-based system with pulse definition circuits (PDCs) that store and process microcode for generating control signals, allowing for the creation of complex pulses through steering and pulse programs, and includes a configuration memory for adjusting parameters, enabling reduced power consumption and increased flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional stimulation circuitry with extensive register banks and flip flops is used, then pulse definition capability is limited, but device complexity and power consumption are reduced
Solution Approach 1:
The patent replaces traditional mechanical/electronic pulse generation methods (using extensive register banks and flip flops) with a microcode-based software control system. The microcontroller executes stored microcode instructions to generate complex stimulation patterns, substituting hardware complexity with programmable flexibility. This allows the same physical hardware to achieve multiple pulse definitions through software rather than requiring dedicated hardware for each pattern.
Solution Approach 2:
The patent changes the fundamental parameter of pulse control from fixed hardware configurations to dynamically programmable parameters stored in memory. By storing microcode with configurable parameters for pulse width, amplitude, frequency, and pattern timing, the system can adapt pulse definitions without physical reconfiguration. This transforms the system from static hardware-based control to dynamic software-based parameter control.
2Adaptability or versatility
If traditional stimulation circuitry with extensive register banks is used, then pulse definition capability is limited, but layout area is reduced
Solution Approach 1:
The patent implements a universal microcontroller-based platform that can generate multiple stimulation patterns through software rather than requiring dedicated hardware circuits for each pattern type. The same physical circuitry executes different microcode programs to produce various pulse widths, frequencies, amplitudes, and temporal patterns, making the hardware universally applicable to multiple therapeutic needs without increasing layout area.
Solution Approach 2:
The patent uses digital microcode copies stored in memory to define pulse patterns rather than physical hardware copies. Each stimulation pattern is represented as a software instruction set that can be stored, modified, and executed without duplicating physical circuitry. This allows multiple pattern definitions to coexist in minimal space compared to hardware implementations.
3Adaptability or versatility
If traditional stimulation circuitry with power-consuming flip flops is used, then simple pulse generation is achieved, but power consumption is reduced
Solution Approach 1:
The patent implements periodic microcode execution cycles where the microcontroller fetches and executes instructions at optimized intervals. By organizing pulse generation as periodic software routines rather than continuous hardware state machine operations, the system can enter low-power states between execution cycles. The microcontroller can sleep during periods when no stimulation is active, significantly reducing average power consumption compared to always-on hardware flip flop circuits.
Solution Approach 2:
The microcontroller-based system manages its own power consumption by intelligently activating circuits only when needed based on the executed microcode instructions. The system can self-regulate power usage by entering sleep modes during inter-pulse intervals and only activating the DAC and output circuits when pulse generation is required, rather than maintaining continuous power to all components as traditional hardware systems do.
Data Source
AI summary
Improved stimulation circuitry for controlling the stimulation delivered by an implantable stimulator is disclosed. The stimulation circuitry includes memory circuitry that stores pulse programs that define pulse shapes, steering programs that define electrode configurations, and aggregate programs that link a selected pulse program with a selected steering program. Each steering program defines the stimulation polarity and the allocation of current of the specified stimulation polarity for each of the pulse generator's electrodes. Each pulse program includes one or more pulse instructions, where each instruction defines the parameters of a single phase of the pulse program. Pulse definition circuits in the stimulation circuitry execute aggregate programs to generate stimulation waveforms, which stimulation waveforms can be generated simultaneously by the different pulse definition circuits.