Galvanically Isolated Pulse Generator With Capacitive Gate Hold
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Solution Overview
Problem
Pulse generators used in consumption meters face high energy consumption when operating optocouplers over long periods or with large pulse widths, especially in battery-powered devices, leading to increased production costs due to the need for additional power supplies for memory logic in edge-triggered optocouplers.
Innovation Solution
A pulse generator design where an optocoupler charges a capacitance via a rectifying component, allowing the field effect transistor to switch based on the voltage drop across the capacitance, which is maintained through leakage currents or a discharge resistor, reducing the need for continuous power supply and enabling efficient energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If an optocoupler is operated with large pulse widths or over longer periods, then the switching state is maintained, but energy consumption increases significantly
Solution Approach 1:
The patent uses periodic pulsed signals to charge the capacitance only when needed to maintain the switching state, rather than continuous operation. The control device outputs pulses at specific intervals to recharge the capacitance that has discharged through leakage currents, achieving energy-efficient periodic maintenance of the optocoupler's switching state.
Solution Approach 2:
The patent introduces a capacitance as an intermediary energy storage element between the control device and the optocoupler. This capacitance stores electrical energy and releases it to maintain the optocoupler's switching state without requiring continuous power from the control device, thereby reducing energy consumption while maintaining duration.
2Duration of action of stationary object
If edge-triggered optocouplers with memory logic are used to maintain switching states, then duration is improved, but device complexity and production costs increase
Solution Approach 1:
The patent extracts the memory function from the optocoupler itself and implements it externally using a capacitance and control logic. Instead of incorporating complex memory logic inside the optocoupler, the solution uses a simple capacitance to store charge and maintain the switching state, thereby reducing device complexity while achieving the same duration improvement.
Solution Approach 2:
The patent uses a simple, inexpensive capacitance component instead of complex memory logic integrated into the optocoupler. The capacitance is easily rechargeable and maintains the switching state through stored energy, providing a cost-effective solution that avoids the high production costs associated with edge-triggered optocouplers containing memory logic.
3Speed
If the capacitance is discharged quickly, then the pulse generator responds faster, but the switching state cannot be maintained for extended periods
Solution Approach 1:
The patent makes the discharge characteristics of the capacitance dynamic by controlling the switching element (such as a transistor or resistor) that determines the discharge path. The discharge resistance can be adjusted or switched to provide fast discharge when needed while allowing slow discharge through leakage currents to maintain the switching state for extended periods, thus achieving both speed and duration requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design achieves high energy efficiency by maintaining switching states for extended periods with minimal energy consumption, allowing the pulse generator to operate effectively without continuous optocoupler energization, thus reducing production costs and energy usage.
Implementation Method 1
the output current of the optocoupler charges a capacitance via a rectifying component, for example a diode, which blocks the capacitance from being discharged via the optocoupler
Implementation Method 2
the voltage drop across the capacitance being the gate voltage of the field effect transistor, the field effect transistor directly or indirectly switching the output of the pulse generator
Implementation Method 3
On the output side, either an impedance is switched, for example via a photoresistor or a photo field effect transistor, or an output current that can be predetermined via the incident light is output, for example by using at least one photodiode on the output side
Data Source
Figure 1
Figure 2~3
AI summary
Pulse generator with galvanically isolated output (17), in particular for a consumption meter (1), wherein a control output (9) of a control unit (10) of the pulse generator (7) is coupled to an input (11) of an optocoupler (12) of the pulse generator (7) in order to output a current controlled by the control unit (10) at the output (13) of the optocoupler (12), wherein the optocoupler (12) is connected to a field-effect transistor (14) such that the output current of the optocoupler (12) charges a capacitor (15) via a rectifying component (16) which prevents the capacitor (15) from discharging via the optocoupler (12), wherein the voltage drop across the capacitor (15) is the gate voltage of the field-effect transistor (14), wherein the field-effect transistor (14) directly or indirectly controls the output (17) of the pulse generator (7). switches.