Photocouplers integrate ΔΣ ADC for high accuracy
Toshiba Electronics Europe has announced a pair of photocouplers for current sensing and voltage sensing in power converters. They achieve high accuracy through the inclusion of a ΔΣ (Delta Sigma) ADC. The TLP7820 and TLP7920 are analogue output type devices; digital output variants are planned for later this year. Target applications include servo amplifiers, inverters, power sources and photovoltaic inverters.
Factory automation equipment, such as servo amplifiers and inverters, now operates with such a high degree of precision that it requires extremely accurate feedback to the MCU on status of the phase current of the motor or the variation of the bus voltage. To meet these requirements, Toshiba has equipped its latest photocouplers with a delta sigma ADC at the input side that enables the devices to achieve a high level of linearity (0.02% at NL200, typical).
TLP7820 and TLP7920 provide a guaranteed Common Mode Transient Immunity of 20kV/μs (typical at VCM=1kV, Ta=25°C), which enables stable operation in electrically noisy environments and makes them particularly suitable for motor control applications. Isolation is through an optical barrier with a guaranteed isolation voltage of 5000VRMS (minimum). Operating temperature range is -40 to +105°C.
A choice of two package types is available: TLP7920 is supplied in an industry-standard DIP8 package; TLP7820 comes in a SO8L package, which is more compact, taking up 30% less board space and featuring a 40% lower profile.