Tag Archive: current


My H-Bridge consume 3ma@3.3v when there is no load and both inputs are zero,

    How can i reduce it ?
    my goal is <100uA
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Q2 and Q8 are SS8550 and Q3 and Q9 are SS8050, other Qs are 2N2222A

Current at output LM1117

See Figure 1 in the LM1117 data sheet for connections for the ‘-ADJ’  version. Note that the LM1117 GND/ADJ pin does not go to GND in the adjustable configuration

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You did not mention exact package type, but the pin#’s narrowed the possibilities. For your application, the connections should look like this

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Pin 1 = ADJ feedback pin

Pin 2 & TAB = Vout pin

Pin 3 = Vin pin

The seemingly low values for R1 and R2 are correct and are to ensure that the minimum load current requirement is always met, and keeps voltage errors due to the Iadj current at a minimum. The TAB=Vout  is the same as Pin 2=Vout on the TO-220, TO-263 and SOT-223 packages, do not connect the TAB to GND.

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The VIPER12A combines a dedicated current mode PWM controller with a high voltage power MOSFET on the same silicon chip.

Typical applications cover off line power supplies for battery charger adapters, standby power supplies for TV or monitors, auxiliary supplies for motor control, etc.

The internal control circuit offers the following benefits: Large input voltage range on the VDD pin accommodates changes in auxiliary supply voltage (This feature is well adapted to battery charger adapter configurations), automatic burst mode in low load condition and overvoltage protection in HICCUP mode.
 

Fixed 60 kHz switching frequency
9 V to 38 V wide range VDDvoltage
Current mode control
Auxiliary undervoltage lockout with hysteresis
High voltage start-up current source
Overtemperature, overcurrent and overvoltage protection with auto-restart
Typical power capability
European (195 – 265 Vac) 8 W for SO-8, 13 W for DIP-8
European (85 – 265 Vac) 5 W for SO-8, 8 W for DIP-8

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The VIPer22A is low cost monolithic smart power devices with integrated PWM controller designed to operate in the wide range input voltage, from 90 to 264Vac.

The VIPer22A internal control circuit offers benefit such as: automatic burst mode in low load condition, overvoltage protection in hiccup mode, and large voltage range on the VDD pin.

This isolated VIPer22A constant current LED driver has been configured to drive 2 to 8 LEDs.

 
700W Amplifier Adjust the amplifier power 700W looks calm, but we requirement not put out of your mind to the adjustment happening forcing transistors, the whole relating to-engagement of frequency offset. It is compulsory to change the current insurance rule which serves to guard the final transistors. Their tendency to happen allowable to keep the transistors in the SOAR characteristics. primary it was needed to evaluate all the necessary resistors and subsequently measured to verify the accuracy of the calculations, it is managed with satisfactory results. Peripheral changes required in support of it to be there able to consistently amplifier to supply power. – First you need to restore the 2k2 resistors stylish string with the LEDs on Zenerovými resistors with upper wattage. be enough 1/2W resistors, power loss next to 80V +-based 1W. – therefore was traded 1k2 resistor in the pointer resistor by the side of 620 ohms.

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Which is the initial reap has doubled, so at this point is the overall gain amplifier 40 and the limit excitation is sufficient to 1V rms. – Předbudiči transistors were replaced by stronger MJE15032/33 since KF467/470 are permitted satellite dish current 20mA – by the side of the exciter output stages are used the same transistors for example the output stage. – add up to of terminals of transistors has been increased to eight pairs – It had to occur to compensate designed for the excitation level by calculation a capacitor 10pF to 47pF + 22K appendage. This led to a slight “gradual” amplifiers, but this did not affect the ensuing parameters. This power is tuned correctly in support of this type of terminal transistors 2SA1943 /2SC5200.

With with the purpose of it is a least assessment next to which the amplifier operates stably exclusive of pass by the side of the rising and falling edges of the genuine.  The ultimate adjustment, the adjustment terminal current protection transistor. The SOAR transistor characteristics shows with the intention of the most allowable radio dish current once the voltage of 1.5 A is ideal in favor of cooling, so it’s essentially not as much of. Therefore, the current protection is customary to 12A, single-arm. This impersonate protection SOAR transistor characteristics. curt-circuit current is regarding 6 A which is about 075A for every transistor. This is far beneath the SOAR characteristics. The mechanical design is relatively clear-cut, the transistors are placed on the two cooling profiles with a height of 66 mm, width 44mm, overall part 260mm. They are twisted contrary to each one other in this way, from the cooling tunnel. Coolers are attaching the nylon aid which allows the compilation of transistors exclusive of washers, and thus better conveying tepla.DPS amplifier next to the top of the tunnel and the transistors are soldered from the underside of PCB.

LM311 is a comparator, It operates from single 5V supply or dual supplies,input current 150 nA, 50 V-50 mA output drive capability. TTL-CMOS compatible output.

The Output is open collector so it can sink current but cannot source, a totem pole output can source and sink. In this Circuit R2 is the source or pull-up.

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The Output being high or low depends on which input is more dominant or positive. If + or non-inverting input is more positive than the – inverting input then output of LM311 is high impedance or high Z as output transistor of LM311 is turned off, but output goes high due to R2 pull-up 1K, so you can apply a load of 10K and above for source. When the – input or inverting input is more positive, output goes Low as transistor turns on, now a current of upto 50mA can sink here, a LED or Relay can be driven.

On turn on C2 capacitor is discharged and pin 3 the inverting input is at a lower potential than pin 2 the non-inverting which is at 2.5V. Hence output goes high and C2 starts charging thru R5, When C2 charges a little beyond 2.5V pin 3 is more dominant and output goes low now, this slowly discharges the C2 bringing the voltage at pin 3 again below 2.5V so output goes high again. This process goes on, hence it oscillates. The charging and discharging is at the rate of R5 * C2 approx. , R3 serves as hysteresis or feedback to ensure clean turn on and off.

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Previous LED lamps with a constant voltage power supply, do not understand the performance of the LED, small light in accordance with the manufacturers to the data of each bead to give to 20MA, weve tested, lamp beads, always burn, and before we know the manufacturers The data is not reliable, we reduce the current use. It was in 2002, do MR16 bulb, billboards and the like applications. I began in 2007 to do the constant current driver, what HV9910, PT4107, PT6901, SN3910, IR, the test more, but the first is the QX9910, some goods, but there are many defective products QX9910 aging The product is also less stable, often have flashing lights, there are still some remaining souvenirs. In my view, in order to do the driver first to get a good chip.

In 2007 when the original, constant current IC is difficult to find, the price of your bizarre, an HV9910 8 yuan, an IRs S2540 25 yuan, in fact, a half-bridge chip, used to intimidate people, but also Japans chip is also used to intimidate, in fact, is the general constant voltage ICs, boring chip away a very long detour, and seriously affected the progress.

HV9910 series in the second generation IC is also very popular, but for technical reasons, the high pressure directly into the IC, easy to blow. Later came out a lot of imitation, imitation is the best SMD802 multiple output short circuit protection, have been widely adopted, with the replacement, this IC is now obsolete.

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This one has a supply current of 70 mA at 1.5V and a LED current of 25 mA at 3.3V (actually 25 millivolts measured across the 1 ohm [2 resistors] in series with the LED’s green wire).  This calculates to an efficiency of 78.6 percent.  The frequency is 250 kHz.

The circuit is almost as simple as the conventional Joule Thief; it requires a diode and 680 pF capacitor in addition to the 1k resistor.  The end of the feedback winding that was normally connected to positive is instead connected to the 1k and 680 pF as shown in the picture.  I used a SS8050 transistor, which is a Fairchild equivalent to the C8050.  It can handle up to 1.5 amp collector current.

The circuit will give more LED current for about the same supply current, or the resistor can be increased to 1.5k to give about the same LED current for less supply current.  The two current sensing resistors that are in parallel on the lower right are optional and can be removed, and the LED’s green wire connected directly to the heavy negative wire.

IR2110 H-Bridge Driver Project

The current flows through the load M – Motor in one direction when S1 and S4 switches are closed and current flows in the other direction when S2 and S3 switches are closed.

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The components that realize the switching action are commonly transistors. Two types of transistors, NPN and PNP for BJTs, N-Channel and P-Channel for MOSFETs are needed for the proper biasing where the high side is P-type and the low side is N-type.

In this project, we use MOSFETs because of their high switching speed and low RDS resistance for low heat dissipation. H-Bridge configuration requires both P and N type MOSFETs but since N-type MOSFETs have improved electrical characteristics, using only N-type for four of the transistors will be ideal. IR2110 half bridge MOSFET and IGBT driver IC allows us to do this. By using a boost-up capacitor, it can bias the high side N-type MOSFETs so we get rid of the P-type.

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The simplest way to drive stepper motor having lower current rating is using ULN2003. The ULN2003 contains seven darlington transistors. The ULN2003 can pass upto 500mA per channel and has an internal voltage drop of about 1V when on. It also contains internal clamp diodes to dissipate voltage spikes when driving inductive loads. The circuit for driving stepper motor using ULN2003 is shown below.

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For higher current torque motors, you can use TIP120. The advantage is that the TIP120 can pass more current along with heat sink. The disadvantages are that the more wiring is required and four TIP120 is used to control the motor.