Key facts
- Brand
- Plessey
- Model
- TDA2085A
- Industry
- Industrial
- Documents
- 2
- Languages
- EN
- Last added
- 2012-04-01
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Plessey TDA2085A Motor Control IC Application Note
The document explains how the TDA2085A IC can be used for motor speed control, covering both open‑loop and closed‑loop operation, feedback voltage generation, and the role of the control amplifier.
It provides detailed circuit diagrams and design equations for the ramp generator, pulse‑timing circuit, triac gate drive, load‑current limiting, LED drive, AC and DC supply arrangements, and system interfacing such as CMOS logic and optical feedback.
Plessey TDA2085A specifications
| Transconductance gain | 100 µA/V |
|---|---|
| Output drive capability | ±25 µA |
| Zero voltage detector reset current | 50 µA |
| Ramp generator current source | 30 µA |
| C3 typical value (50 Hz supply) | 47 nF ±10% |
| Triac pulse width | ≈70 µs |
| LED drive additional current | ≈0.5 mA |
All Plessey TDA2085A documents by type
How to use the product for one specific task, with worked examples.
Ratings, dimensions and ordering codes, for selection and design work.
Questions answered in these manuals
What current triggers the zero voltage detector reset?
The zero voltage detector resets when the input current is between 50 µA.
How is the ramp generator current set?
The ramp generator uses an internally generated 30 µA current source (Ir).
What current does the zero‑voltage detector use to reset the timing circuit?
It resets when the input current falls between 50 µA.