U217B B

User Manual:

Open the PDF directly: View PDF PDF.
Page Count: 11

Scroll down to view the document on your mobile browser.
U217B/ U217B-FPTELEFUNKEN SemiconductorsRev. A1, 24-May-96 1 (11)Zero Voltage Switch with Adjustable RampDescriptionThe integrated circuit, U217B, is designed as a zero-voltage switch in bipolar technology. It is used to controlresistive loads at mains by a triac in zero-crossing mode.A ramp generator allows to realize power control functionby period group control, whereas full wave logicguarantees that full mains cycles are used for loadswitching.FeaturesDirect supply from the mainsCurrent consumption ≤ 0.5 mAVery few external componentsFull wave drive – no dc current component in the loadcircuitNegative output current pulse typ. 100 mA – short circuit protectedSimple power controlRamp generatorReference voltageApplicationsFull wave power controlTemperature regulationPower blinking switchPackage: DIP8, SO8Block DiagramRampgeneratorPulseamplifierComparatorR118 k2 WD1BYT86/800 LTIC236N95 10872Synchronization SupplyFull wave logic+–Reference voltage1.25 V134R4100 k 2 8 5C22.2 F/10 VR515 kminmax100 kR658 k76220 kC1100 R3Load1000 WVM=230 V~N(Rsync)R2(250 V~)GMT2MT1GND+100 F/16 VFigure 1. Block diagram with typical circuit, period group control 0 to 100%
U217B/ U217B-FPTELEFUNKEN SemiconductorsRev. A1, 24-May-962 (11)General DescriptionThe integrated circuit, U217B, is a triac controller for thezero crossing mode. It is meant to control power inswitching resistive loads of mains supply.Information regarding supply sync. is provided at Pin 8via resistor RSync.To avoid dc load on the mains, full wave logic guaranteesthat complete mains cycles are used for load switching.A fire pulse is released when the inverted input of thecomparator is negative (Pin 4) with respect to the non–inverted input (Pin 3) and internal reference voltage.A ramp generator with free selectable duration is possiblewith capacitor C2 at Pin 2 which provides not onlysymmetrical pulse burst control (figure 3), but alsocontrol with superimposed proportional band (figure 10).Ramp voltage available at capacitor C2 is decoupledacross emitter follower at Pin l. To maintain the lampflicker specification, ramp duration is adjusted accordingto the controlling load. In practice, interference should beavoided (temperature control). Therefore in such cases atwo point control is preferred to proportional control. Onecan use internal reference voltage for simple applications.In that case Pin 3 is inactive and connected to Pin 7(GND), figure 9.Rampcontrol1C2–VS95 113062Figure 2. Pin 1 internal network95 11307V11.4 V7.3 V–VS(Pin5)TVmintFinal voltageInitial voltageVmaxFigure 3. Firing Pulse Width tp, (Figure 4)This depends on the latching current of the triac and itsload current. The firing pulse width is determined by thezero crossing identification which can be influenced withthe help of sync. resistance, Rsync, (figure 6).tp = 2arc. sin IL VMP2whereasIL= Latching current of the triacVM= Mains supply, effectiveP = Power load (user’s power)Total current consumption is influenced by the firingpulse width, which can be calculated as follows:RsyncVM2sin ( tp2)–0.6 V3.5 10–5A–49 k0.010.101.0010.0010 100 1000 10000t ( ms )P ( W )96 11939pIL ( mA)10020050Vmains = 230 V∼Figure 4. 0 300 600 900 1200040080012002000R ( k )Synctp ( s )150095 99781600VM=230V ACTamb=25°CFigure 5.

Navigation menu