HV9921 Supertex, Inc., HV9921 Datasheet
HV9921
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HV9921 Summary of contents
Page 1
... The LED string is driven at constant current, thus providing constant light output and enhanced reliability. The output current is internally fi xed at 20mA for HV9921. The peak current control scheme provides good regulation of the output current throughout the universal AC line voltage range 264VAC or DC input voltage 400V ...
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... W = Code for week sealed H21YW Y = Code for year sealed = “Green” Packaging SOT-89 (N8) Max Units Conditions - V --- - V --- - V --- - mV --- 350 µ 8.5V, V DD(EXT) DRAIN - V --- 210 Ω 20mA DRAIN 5 400V DRAIN - mA --- 25.5 mA --- 400 ns --- 650 ns --- 13 µs --- < +85°C. A HV9921 VDD GND = 40V ...
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... Junction Tem perature, ° DRAIN Voltage 25° 125° DRAIN Voltage, V HV9921 110 40 40 ...
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... • ΔI O OFF the forward voltage of the LED string time of the HV9921. The output current in the LED string (I is calculated then as (Δ where I ripple current introduces a peak-to-average error in the output current setting that needs to be accounted for ...
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... T is the minimum blanking time of 200ns, and BLANK(MIN the maximum instantaneous input voltage. IN(MAX) Estimating Power Loss Discharging the parasitic capacitance C the HV9921 is responsible for the bulk of the switching power loss. It can be estimated using the following equation: ⎛ 2 ⎞ ...
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... T SPIKE 100mA Figure 2. Universal 85-264VAC LED Lamp Driver Line VRD1 85-264V F1 Step 5. Estimating power dissipation in HV9921 at 264VAC using (8) and (10) Let us assume that the overall effi ciency η = 0.7. Switching power loss: P ≈ SWITCH P ≈ 120mW 1 SWITCH ≈ ⋅ ...
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... Figure 4. Switch-Off Transition. Ch1: V Figure 6. Switch-Off Transition. Ch1: V Figure 6. Switch-Off Transition. Ch1: V GND VDD T = OFF 10.5µ REF - 300ns BLANK HV9921 7 DRAIN DRAIN ZERO VOLTAGE ZERO VOLTAGE TRANSITION TRANSITION DRAIN DRAIN DRAIN Regulator 7.5V R HV9921 , Ch3 Ch3: I DRAIN DRAIN , Ch3 Ch3: I DRAIN DRAIN ...
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... RF emission. The switching node copper area connected to the DRAIN pin should be located as of the HV9921, the anode of D1 and the inductor L1 needs to be minimized. A large switching node area can increase high frequency radiated EMI. ...
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... Bottom View Symbol A MIN .170 Dimension NOM - (inches) MAX .210 Drawings not to scale Side View .014 .014 .175 - - - .022 .022 .205 9 HV9921 .125 .080 .095 .045 - - - - .165 .105 .105 .055 L .500 - - ...
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... MAX 1.60 0.56 JEDEC Registration TO-243, Variation AA, Issue C, July 1986. Drawings not to scale. (The package drawing(s) in this data sheet may not refl ect the most current specifi cations. For the latest package outline information go to http://www.supertex.com/packaging.html.) DSFP# HV9921 A122707 ...