• ROHM’s new IC sequence delivers low standby energy and improves communication reliability in dwelling home equipment
  • Designers can now remove any advanced design utilizing discrete elements and on the identical time, take away the combination of photocouplers

The demand for good home equipment and IoT functions is on the rise, having added communication performance (i.e. Wi-Fi) to dwelling home equipment. As it’s vital for such gadgets to all the time be ON to keep up communication, there’s additionally a necessity for discount of standby energy consumption to round 0.5W, calling for decrease standby energy consumption by the motor and energy provide blocks together with modern new applied sciences.

Many home equipment require a zero-cross detection circuit for detecting the 0V level (zero-cross level) of the AC waveform to offer environment friendly management of each motors and MCUs. Nevertheless, when it comes to energy consumption, typical zero-cross detection circuits make the most of a photocoupler that accounts for practically half of the standby energy of the whole system.

As a way to present a greater answer, ROHM has developed the BM1ZxxxFJ, an built-in zero-cross detection IC sequence that’s optimised for dwelling home equipment reminiscent of vacuum cleaners, washing machines and air conditioners.

The built-in zero-cross detection IC supplies designers with a turn-key zero-cross detector, eliminating any advanced design utilizing discrete elements. Moreover, this built-in answer doesn’t use a photo-coupler, due to this fact, it additional reduces standby present consumption and will increase long-term reliability.

The BM1ZxxxFJ sequence reduces standby energy consumption of the zero-cross circuit to simply 0.01W whereas repeatedly powering the system. The error in delay time (which varies relying on the AC voltage) that exists with typical photocoupler-equipped zero-cross detection circuits is proscribed to ±50µs or much less. This permits effectively driving the motors – even with the completely different AC provide voltages – in addition to MCUs (which is tough to attain utilizing typical zero-cross detection circuits). On the identical time, eliminating the necessity for a photocoupler contributes to better software reliability by lowering dangers associated to age-based degradation.

What’s Zero Cross Level?

A zero-cross detection circuit is required in dwelling home equipment that provide energy from an AC outlet to detect the zero-cross level (which is the 0V level of the AC waveform) to effectively management each motors and MCUs. In consequence, bettering zero-cross detection accuracy permits for much more environment friendly motor and MCU management. And when the motor is stopped, pulse management supplies better circuit security by reliably stopping the voltage at 0V.

Key Options

1. Photocoupler-less zero-cross detection circuit design minimises software standby energy consumption

Typical zero-cross detection circuits generally make the most of a photocoupler and transistor that accounts for practically half of the standby energy consumption of the whole software. After analysing a whole lot of energy provide patterns in numerous environments, ROHM’s IC is able to detecting zero-cross with out a photocoupler.

Together with lowering the variety of elements, the brand new design delivers a standby energy consumption near zero (0.01W). And in motor functions, it’s doable to additional lower element depend together with standby energy consumption by eliminating the motor enter voltage detection circuit.

2. Contributes to improved reliability and effectivity in dwelling home equipment

Utilizing a photocoupler entails dangers that embody efficiency degradation as a result of deterioration in luminous depth over time. Eliminating the photocoupler not solely reduces this failure threat but in addition limits the delay time error, which may range relying on the AC voltage, to ±50μs or much less. This makes it doable to effectively drive motors even with assorted provide voltages (100-230V) – in addition to MCUs, which is tough or unattainable to attain utilizing typical zero-cross detection circuits.

3. Simply substitute typical zero-cross detection circuits

The brand new sequence helps the waveforms (pulse/edge) and circuit topologies (normal rectification/double rectification) utilised in typical zero-cross detection circuits, permitting customers to simply substitute normal zero-cross detection circuits geared up with a photocoupler with out requiring software program modifications.

4. Built-in voltage clamp perform protects the downstream MCU

The BM1ZxxxFJ sequence is appropriate with enter voltages as much as 600V and performs voltage division to the output under the utmost rated voltage of MCU and drive normal MCUs as much as 5V. A voltage clamp perform can also be included that ensures the enter voltage doesn’t exceed 4.8V, defending the MCU even when irregular voltages are generated in excessive voltage drive functions reminiscent of air conditioners.

The BM1ZxxxFJ sequence helps each pulse and edge waveforms utilized in dwelling equipment specs, eliminating the necessity for software program modifications when changing typical zero-cross detection circuits. 6 fashions are supplied to make sure compatibility with a variety of dwelling home equipment.

5. Helps Two Output Waveforms Relying On Specs

The sequence is now in mass manufacturing. An built-in zero-cross detection IC growth board can also be accessible that integrates an influence provide for driving ROHM’s built-in zero-cross detection IC, facilitating system analysis. This analysis board is designed to simplify the decision-making course of for designers when contemplating alternative of present circuits utilizing a photocoupler.