Zero Voltage Switch Power Controller

UAA2016 Zero Voltage Switch Power Controller The UAA2016 is designed to drive triacs with the Zero Voltage technique which allows RFI−free power regulation of resistive loads. Operating directly on the AC power line, its main application is the precision regulation of electrical heating systems such as panel heaters or irons. A built−in digital sawtooth waveform permits proportional temperature regulation action over a ±1°C band around the set point. For energy savings there is a programmable temperature reduction function, and for security a sensor failsafe inhibits output pulses when the sensor connection is broken. Preset temperature (i.e. defrost) application is also possible. In applications where high hysteresis is needed, its value can be adjusted up to 5°C around the set point. All these features are implemented with a very low external component count. Features http://onsemi.com ZERO VOLTAGE SWITCH POWER CONTROLLER MARKING DIAGRAMS 8 1 PDIP−8 P SUFFIX CASE 626 UAA2016P AWL YYWWG • • • • • • • • • Zero Voltage Switch for Triacs, up to 2.0 kW (MAC212A8) Direct AC Line Operation Proportional Regulation of Temperature over a 1°C Band Programmable Temperature Reduction Preset Temperature (i.e. Defrost) www.DataSheet4U.com Sensor Failsafe Adjustable Hysteresis Low External Component Count Pb−Free Packages are Available 8 8 1 SOIC−8 D SUFFIX CASE 751 1 x = A or D A = Assembly Location WL, L = Wafer Lot YY, Y = Year WW, W = Work Week G, G = Pb−Free Package (Note: Microdot may be in either location) 2016x ALYW G Failsafe 3 Sense Input 4 Temperature Reduction + − Sampling Full Wave Logic Internal Reference UAA2016 Pulse Amplifier 6 Output 7 +VCC PIN CONNECTIONS Vref 1 Hys. Adj. 2 Sensor 3 Temp. Reduc. 4 8 7 6 5 (Top View) Sync VCC Output VEE + + + 1/2 4−Bit DAC 2 Hysteresis Adjust Synchronization Supply Voltage 11−Bit Counter (Sawtooth Generator) ORDERING INFORMATION See detailed ordering and shipping information in the package dimensions section on page 9 of this data sheet. 1 Voltage Reference 8 Sync 5 VEE Figure 1. Representative Block Diagram © Semiconductor Components Industries, LLC, 2006 1 January, 2006 − Rev. 9 Publication Order Number: UAA2016/D UAA2016 MAXIMUM RATINGS (Voltages referenced to Pin 7) Rating Supply Current (IPin 5) Non−Repetitive Supply Current, AC Synchronization Current Pin Voltages (Pulse Width = 1.0 ms) Symbol ICC ICCP Isync VPin 2 VPin 3 VPin 4 VPin 6 IPin 1 IO PD RqJA TA Value 15 200 3.0 0; Vref 0; Vref 0; Vref 0; VEE 1.0 150 625 100 − 20 to + 85 Unit mA mA mA V Vref Current Sink Output Current (Pin 6), (Pulse Width < 400 ms) Power Dissipation Thermal Resistance, Junction−to−Air Operating Temperature Range mA mA mW °C/W °C Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied, damage may occur and reliability may be affected. ELECTRICAL CHARACTERISTICS (TA = 25°C, VEE = −7.0 V, voltages referred to Pin 7, unless otherwise noted.) Characteristic Supply Current (Pins 6, 8 not connected), (TA = − 20° to + 85°C) Stabilized Supply Voltage (Pin 5), (ICC = 2.0 mA) Reference Voltage (Pin 1) Output Pulse Current (TA = − 20° to + 85°C), (Rout = 60 W, VEE = − 8.0 V) Output Leakage Current (Vout = 0 V) Output Pulse Width (TA = − 20° to + 85°C) (Note 1), (Mains = 220 Vrms, Rsync = 220 kW) Comparator Offset (Note 5) Sensor Input Bias Current Sawtooth Period (Note 2) Sawtooth Amplitude (Note 6) Temperature Reduction Voltage (Note 3), (Pin 4 Connected to VCC) Internal Hysteresis Voltage, (Pin 2 Not Connected) Additional Hysteresis (Note 4), (Pin 2 Connected to VCC) Failsafe Threshold (TA = − 20° to + 85°C) (Note 7) Symbol ICC VEE Vref IO IOL TP Voff IIB TS AS VTR VIH VH VFSth Min − −10 −6.5 90 − 50 −10 − − 50 280 − 280 180 Typ 0.9 −9.0 −5.5 100 − − − − 40.96 70 350 10 350 − Max 1.5 −8.0 −4.5 130 10 100 +10 0.1 − 90 420 − 420 300 Unit mA V V mA mA ms mV mA sec mV mV mV mV mV 1. Output pulses are centered with respect to zero crossing point. Pulse width is adjusted by the value of Rsync. Refer to application curves. 2. The actual sawtooth period depends on the AC power line frequency. It is exactly 2048 times the corresponding period. For the 50 Hz case it is 40.96 sec. For the 60 Hz case it is 34.13 sec. This is to comply with the European standard, namely that 2.0 kW loads cannot be connected or removed from the line more than once every 30 sec. The inertia of most heating systems combined with the UAA2016 will comply with the European Standard. 3. 350 mV corresponds to 5°C temperature reduction. This is tested at probe using internal test pad. Smaller temperature reduction can be obtained by adding an external resistor between Pin 4 and VCC. Refer to application curves. 4. 350 mV corresponds to a hysteresis of 5°C. This is tested at probe using internal test pad. Smaller additional hysteresis can be obtained by adding an external resistor between Pin 2 and VCC. Refer to application curves. 5. Parameter guaranteed but not tested. Worst case 10 mV corresponds to 0.15°C shift on set point. 6. Measured at probe by internal test pad. 70 mV corresponds to 1°C. Note that the proportional band is independent of the NTC value. 7. At very low temperature the NTC resistor increases quickly. This can cause the sensor input voltage to reach the failsafe threshold, thus inhibiting output pulses; refer to application schematics. The corresponding temperature is the limit at which the circuit works in the typical application. By setting this threshold at 0.05 Vref, the NTC value can increase up to 20 times its nominal value, thus the application works below − 20°C. http://onsemi.com 2 UAA2016 S2 RS S1 Rdef R2 R1 R3 3 Sense Input 4 Failsafe + − Sampling Full Wave Logic UAA2016 MAC212A8 Pulse Amplifier 6 Rout Output 220 Vac Load 7 +VCC CF NTC Temp. Red. + + + 1/2 Internal Reference 4−Bit DAC 2 HysAdj 11−Bit Counter 1 Vref Sync Rsync 8 VEE RS 5 Synchronization Supply Voltage Figure 1. Application Schematic APPLICATION INFORMATION (For simplicity, the LED in series with Rout is omitted in the following calculations.) Triac Choice and Rout Determination The load current is then: I Load + (Vrms 2 sin(2pft)–V )R TM L Depending on the power in the load, choose the triac that has the lowest peak gate trigger current. This will limit the output current of the UAA2016 and thus its power consumption. Use Figure 4 to determine Rout according to the triac maximum gate current (IGT) and the application low temperature limit. For a 2.0 kW load at 220 Vrms, a good triac choice is the ON Semiconductor MAC212A8. Its maximum peak gate trigger current at 25°C is 50 mA. For an application to work down to − 20°C, Rout should be 60 W. It is assumed that: IGT(T) = IGT(25°C)  exp (−T/125) with T in °C, which applies to the MAC212A8. Output Pulse Width, Rsync where VTM is the maximum on state voltage of the triac, f is the line frequency. Set ILoad = ILatch for t = TP/2 to calculate TP. Figures 6 and 7 give the value of TP which corresponds to the higher of the values of IHold and ILatch, assuming that VTM = 1.6 V. Figure 8 gives the Rsync that produces the corresponding TP. RSupply and Filter Capacitor The pulse with TP is determined by the triac’s IHold, ILatch together with the load value and working conditions (frequency and voltage): Given the RMS AC voltage and the load power, the load value is: RL = V2rms/POWER With the output current and the pulse width determined as above, use Figures 9 and 10 to determine RSupply, assuming that the sinking current at Vref pin (including NTC bridge current) is less than 0.5 mA. Then use Figure 11 and 12 to determine the filter capacitor (CF) according to the ripple desired on supply voltage. The maximum ripple allowed is 1.0 V. Temperature Reduction Determined by R1 (Refer to Figures 13 and 14.) http://onsemi.com 3 UAA2016 Proportional Band Room Temperature T (°C) Overshoot Time (minutes, Typ.) Time (minutes, Typ.) Heating Power P(W) Time (minutes, Typ.) Proportional Temperature Control D Reduced Overshoot D Good Stability Time (minutes, Typ.) ON/OFF Temperature Control D Large Overshoot D Marginal Stability Figure 2. Comparison Between Proportional Control and ON/OFF Control TP is centered on the zero−crossing. TP AC Line Waveform IHold ILatch Gate Current Pulse T+ P 14 x Rsync ) 7 Vrms 2 x pf 105 (μs) f = AC Line Frequency (Hz) Vrms = AC Line RMS Voltage (V) Rsync = Synchronization Resistor (W) Figure 3. Zero Voltage Technique http://onsemi.com 4 UAA2016 CIRCUIT FUNCTIONAL DESCRIPTION Power Supply (Pin 5 and Pin 7) Sawtooth Generator The application uses a current source supplied by a single high voltage rectifier in series with a power dropping resistor. An integrated shunt regulator delivers a VEE voltage of − 8.6 V with respect to Pin 7. The current used by the total regulating system can be shared in four functional blocks: IC supply, sensing bridge, triac gate firing pulses and zener current. The integrated zener, as in any shunt regulator, absorbs the excess supply current. The 50 Hz pulsed supply current is smoothed by the large value capacitor connected between Pins 5 and 7. Temperature Sensing (Pin 3) The actual temperature is sensed by a negative temperature coefficient element connected in a resistor divider fashion. This two element network is connected between the ground terminal Pin 5 and the reference voltage − 5.5 V available on Pin 1. The resulting voltage, a function of the measured temperature, is applied to Pin 3 and internally compared to a control voltage whose value depends on several elements: Sawtooth, Temperature Reduction an