[introduction] STMicroelectronics rolled out switch of intelligence of new generation car nearly, use in-house A/D converter to provide the digital information of concerned load current. In the article, we will discuss the necessity of the mains switch that has voltaic induction function, understand contemporary switch how to realize this function.

STMicroelectronics rolled out switch of intelligence of new generation car nearly, use in-house A/D converter to provide the digital information of concerned load current. In the article, we will discuss the necessity of the mains switch that has voltaic induction function, understand contemporary switch how to realize this function.

ST expresses, new high margin switch is the market last detect digital electric current regard its as total number word piece on the product of the one part of diagnostic function. The picture is offerred by STMicroelectronics

Mains switch needs to protect a function

High margin switch is used at all sorts of cars and industrial application normally. To laden power supply when, the diagnosis that executive place needs and mechanism of prevention of accidents are very principal.

For example, a main problem is the short circuit that outputs systematic ground connection from switch. If allocate the wiring harness of power source batholith of car of not careful bring into contact with, switch should cut off output power source instantly before switch, wiring harness and power source damage.

To ensure in the light of this kind of breakdown the circumstance provides strong protection, the diagnosis that contemporary intelligence mains switch includes a variety of differring and breakdown detect function, press too for example, owe pressure, overheat, overload and short circuit protection.
 
Accurate electric current detects

In certain applying, our need is accurate measure load current. For example, in car seat heater, the quantity of heat of generation depends on the electric current that has shed switch. To control quantity of heat, closed circuit system must monitoring load current undertakes be adjustmented necessarily. Flu of high accuracy report measures the torque that still can realize electric machinery to control application to control.
Accurate electric current detects make we can be in drive detects when a group of shunt-wound LED circumstance of open circuit load. Enough electricity detects the mechanism can detect the breakdown circumstance of open a way of a LED in one pile LED.
 
Imitate electric current detects

The intelligent mains switch that great majority has voltaic induction function is offerred with signal of imitate of load current proportionate. The imitate electric current of the TPS1H100-Q1 that issued a graph to show Texas Instruments detects mechanism.

TPSxHxxx electric current detects circuit. The picture is offerred by heart state apparatus

Below this kind of circumstance, voltaic lens develop attacks use at be in " inductive MOSFET " found in branch with electric current of proportionate of I OUT of output electric current. This are duplicate electric current brings a foot to convey to through SNS detect resistor R SNS. Accordingly, detect the voltage of two end and load current become resistance direct ratio.

SNS brings the RC between foot and ADC input low connect filter purify detect the high frequency heft that does not need in resistor voltage. Convey the output after filtering to control the A/D converter of the MCU of mains switch next. Output electric current and in comparing I SNS faradicly to be expressed in data of parts of an apparatus, give out, because this MCU can decide load current easily.   
 
Digital electric current detects

Meaning law semiconductor rolled out driver of high side of VN9D30Q100F and VN9D5D20FN nearly, the number that can export load current is worth. The functional-block diagram of VN9D30Q100F is shown as follows.

The block diagram of VN9D30Q100F. The picture is offerred by STMicroelectronics

If what you see, this equipment uses in-house ADC to will output electric current to be worth digitlization. Compositive ADC is a converter of 10 SAR A/D. Because VN9D30Q100F has 6 different channels, imitate multichannel answer with implement use at will be being joined by the passageway of monitoring amplifier is mixed ADC piece.

SPI interface is used at will digitlizing information to send MCU. ADC compositive the amount that to switch the resource of side of OK and economic MCU in enclosing reduces exterior component. Carry this kind of kind, new facility can reduce the use of the workload of MCU and I/O.

STMicroelectronics claims, these new parts of an apparatus or appliance are first provides function of induction of digital electric current intelligence mains switch on the market. Institute of as above plan is shown, ADC still can read in-house sensor extraction temperature information digitlization.
 
Electric current detects precision

What should notice is, below inferior load current, imitate and digital electric current detect methodological electric current detects the precision of circuit can be shown reduce. For example, the TPS1H100-Q1 of use TI, [The electric flu of I_{OUT} Geq 1A] measures precision to be ± 3% ; However, to about the I OUT of 5 MA, precision is ± 80% .

Next graphs showed the overall trend that drops in the precision below inferior output electric current.

Electric current detects precision. The picture is offerred by heart state apparatus

The digital electricity that uses in the ST product that releases nearly detects the mechanism also observed similar trend. If the precision that issued a watch to show VN9D30Q100F wheres inferior output is reduced below electric current.

Digital electric current detects. The picture is offerred by STMicroelectronics

Other and characteristic

VN9D30Q100F and VN9D5D20FN only for of power supply of 12 V batteries apply and design. New parts of an apparatus or appliance uses technology of ST generation VIPower* M0-9, perpendicular MOSFET and logic of 3.3 V number and circuit of high accuracy imitate combine will efficient 40 V groove to be enclosed in a 6 Mm X 6 Mm QFN in.

VN9D30Q100F has Ω of two 33 M and channel of Ω of 4 90 M. VN9D5D20FN has Ω of two 7.6 M and channel of Ω of two 20 M. These parts of an apparatus are compositive still a resolution is the PWM generator of 0.1% , conduce to processing lamp moving the function such as light.

Avoid duty statement: The article is reprint an article, reprint this article purpose to depend on passing more information, the person that copyright puts in original work ‘s charge is all. If involve work copyright issue,article place uses video, picture, written language, contact please small make up undertake handling.