Product category:
Power Supply ICs and Controllers
News Release from: Allegro MicroSystems Europe
Edited by the Electronicstalk Editorial
Team on 10 May 2007
Paper on high-speed low-noise current
sensing
Innovative developments in high-speed low-noise current sensing will be presented in a paper given at the PCIM Conference, taking place in Nuremberg between 22nd and 24th May.
Innovative developments in high-speed low-noise current sensing will be presented in a paper being given by John Cummings of Allegro MicroSystems at the PCIM Conference, taking place in Nuremberg between 22nd and 24th May The paper shows how the high-bandwidth performance normally found in closed-loop configurations can be met with a low-cost open-loop architecture
This article was originally published on Electronicstalk on 30 Aug 2000 at 8.00am (UK)
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Allegro designers have created a high-bandwidth open-loop part with fundamentally lower noise coupled with fast response time, leading to the realisation of compact surface-mount current sensors with a high level of system integration.
The key advantages for open-loop Hall-effect current sensors are the small form factor and reduced overall cost.
Historically, primary disadvantages of this approach have been bandwidth and response-time performance.
There is an inherent conflict in realising a high-bandwidth, low noise, open-loop Hall-effect current sensor.
The reason for this is that the chopper stabilisation circuit, which is used to virtually eliminate offset error, can only switch as fast as the dielectric relaxation frequency limit that the Hall element will allow.
Although the chopper circuit is useful in reducing offset error, it also is a major source of noise contribution within the device.
The PCIM paper presents recent developments in fabrication technology and high-speed chopper stabilisation circuitry, which improve response time, increase bandwidth, and improve the signal-to-noise ratio on the output of the device.
Ever-present demands for size and cost reductions have also driven innovation in Hall-effect current sensors.
This size reduction correspondingly increases the capacitive coupling between the sensed current and the silicon.
An innovative shield process - also described in the paper - has been developed to reduce this effect.
The Allegro MicroSystems families of Hall-effect sensors, including the latest programmable linear devices and gear-tooth sensors for automotive and industrial applications, will be on display at the Sensor and Test Exhibition, which is being held alongside PCIM in a separate hall in The Nuremberg Exhibition Centre.
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