Taipei, Saturday, Sep 23, 2017, 13:45

Technology Front

Most Efficient and Robust Current Sensing Optocoupler Solution

Published: Sep 01,2016

727 Read

Broadcom Limited announced a new optically isolated sigma-delta modulator device, the Avago ACPL-C799, designed for a wide range of industrial applications including servo drives and motors. The new device features a low differential input range of +/-50 mV allowing designers to reduce power dissipation across a current-sensing shunt resistor in servo drive and motor applications.

More on This

Broadcom Announces Availability of Ecosystem of 802.11ax Solutions

Broadcom launched Max WiFi, the family of connectivity solutions using the next Wi-Fi standard, 802.11ax. The Max WiFi chips enable up to four times faster download speeds...

Broadcom Announces High-Performance Data Center SoC with Integrated NetXtreme Ethernet Controller

The Broadcom NetXtreme S-Series BCM58800 family of data center System-on-Chip (SoC) devices are purpose-built to enable solutions in the evolving data center...

Compared to previous generation products with an input range of +/-200 mV, the ACPL-C799 enables the use of a smaller shunt resistor with one-quarter the value, thereby eliminating 75 percent (75%) of shunt resistor’s power losses. Despite the reduced input voltage range, the device delivers superb SNR, ENOB and offset drift performance, enabling a high precision motor control in space constrained, high temperature environments.

The ACPL-C799 is a 1-bit, second-order sigma-delta (Σ-Δ) modulator that converts an analog input signal into a high-speed data stream with galvanic isolation based on optical coupling technology. The ACPL-C799 operates from a 5V power supply with dynamic range of 77 dB with an appropriate digital filter. The differential inputs of ±50 mV (full scale ±80 mV) are ideal for direct connection to shunt resistors or other low-level signal sources in applications such as motor phase current measurement.

The analog input is continuously sampled by a means of sigma-delta over-sampling using an on-board clock. The signal information is contained in the modulator data, as a density of ones with data rate of 10 MHz, and the data are encoded and transmitted across the isolation boundary where they are recovered and decoded into high-speed data stream of digital ones and zeros. The original signal information can be reconstructed with a digital filter. The serial interface for data and clock has a wide supply range of 3 V to 5.5 V.

Combined with superior optical coupling technology, the modulator delivers high noise margins and excellent immunity against isolation-mode transients. With 0.5 mm minimum distance through insulation (DTI), the ACPL-C799 provides reliable reinforced insulation and high working insulation voltage, which is suitable for fail-safe designs. This outstanding isolation performance is superior to alternatives including devices based on capacitive- or magnetic-coupling with DTI in micro-meter range. Offered in a Stretched SO-8 (SSO-8) package, the isolated ADC delivers the reliability, small size, superior isolation and over-temperature performance motor drive designers need to accurately measure current at much lower price compared to traditional current transducers.

comments powered by Disqus