Key facts
- Brand
- STMicroelectronics
- Model
- AN308
- Category
- Other Electronics
- Documents
- 2
- Languages
- EN
- Last added
- 2012-08-06
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STMicroelectronics AN308 TRIAC Analog Control Circuits Application Note
The document discusses various triggering methods for TRIACs used with inductive loads. It evaluates circuits synchronized across the TRIAC voltage versus those synchronized by the mains voltage, highlighting issues like asymmetrical operation and load dependency.
A specific circuit suitable for industrial applications is proposed, utilizing a pulse train synchronization method to ensure perfect symmetry of current regardless of the phase shift or variable cos phi values.
STMicroelectronics AN308 specifications
| Output voltage | 19 V @ 3.42 A continuous operation |
|---|---|
| Input mains range | 90 + 264 Vac - frequency 45 + 65Hz |
| Standby consumption | <100 mW @ 230 Vac |
| Average efficiency | better than 89% |
| Dimensions | 58x121 mm |
Source: STMicroelectronics AN3089 19V 65W Quasi-Resonant Flyback Adapter Application Note
All STMicroelectronics AN308 documents by type
How to use the product for one specific task, with worked examples.
Questions answered in these manuals
What is the main disadvantage of triggering synchronized across the TRIAC voltage?
It can result in unacceptable asymmetrical operation, which is dangerous for highly inductive loads.
From: STMicroelectronics AN308 TRIAC Analog Control Circuits Application Note
How does the industrial application circuit prevent asymmetrical operation?
It maintains the triggering signal during each half wave using a pulse train to retrigger the TRIAC.
From: STMicroelectronics AN308 TRIAC Analog Control Circuits Application Note
What is the maximum switching frequency?
The maximum switching frequency is set at about 165 kHz.
From: STMicroelectronics AN3089 19V 65W Quasi-Resonant Flyback Adapter Application Note
What MOSFET is used in the design?
The design uses a standard 800 V, STF7NM80 MOSFET in a TO-220FP package.
From: STMicroelectronics AN3089 19V 65W Quasi-Resonant Flyback Adapter Application Note