Electronic Components Datasheet Search |
|
HV9925 Datasheet(PDF) 7 Page - Supertex, Inc |
|
HV9925 Datasheet(HTML) 7 Page - Supertex, Inc |
7 / 10 page 7 NR021506 HV9925 Step 1. Calculating L1. The output voltage V O = 10 · VF ≈ 41V (max.). Use equation (1) assuming a 30% peak-to-peak ripple. Select L1 68mH, I=30mA. Typical SRF = 170KHz. Calculate the coil capacitance. Step 2. Selecting D1 Usually, the reverse recovery characteristics of ultra- fast rectifiers at I F = 20~50mA are not provided in the manufacturer’s data books. The designer may want to experiment with different diodes to achieve the best result. Select D1 MUR160 with V R = 600V, trr rrrr ≈ 20ns (IF = 20mA, IRR = 100mA) and C J ≈ 8pF (VF>50V). Step 3. Calculating total parasitic capacitance using: (3) Step 4. Calculating the leading edge spike duration using: (4), (5) Step 5. Estimating power dissipation in HV9925 at 264VAC using (8) and (10) Let us assume that the overall efficiency η = 0.7. Switching power loss: Switching power loss: Minimum duty ratio: Minimum duty ratio: Conduction power loss: Conduction power loss: Total power dissipation at V Total power dissipation at V AC(max) AC(max) Total power dissipation at V Total power dissipation at V Total power dissipation at V Total power dissipation at V : Step 6. Selecting input capacitor C IN Select C IN ECQ-E4104KF by Panasonic (0.1µF, 400V, Metalized Polyester Film). Design Example 2 Let us now design a PWM-dimmable LED lamp driver using the HV9925: Input: Universal AC, 85-135VAC Output Current: 50mA Load: String of 12 LED (Power TOPLED® by ® ® OSRAM, V F = 2.5V max. each) The schematic diagram of the LED driver is shown in Fig.3. We will use an aluminum electrolytic capacitor for C IN in order to prevent interruptions of the LED current at zero crossings of the input voltage. As a“rule of thumb”, 2~3μF per each watt of the input power is required for C IN in this case. Step 1. Calculating L1. The output voltage V O = 12 · VF = 30V (max.). Use equation (1) assuming a 30% peak-to-peak ripple. Select L1 22mH, I = 60mA. Typical SRF = 270KHz. Calculate the coil capacitance. Step 2. Selecting D1 Select D1 ES1G with V R = 400V, trr rrrr ≈ 35ns and CJ < 10pF. Step 3. Calculating total parasitic capacitance using: (3) Step 4. Calculating the leading edge spike duration using (4), (5) Step 5. Estimating power dissipation in HV9925 at 135VAC using (6), (7) and (9) Switching power loss: Switching power loss: L V s mA mH 1 41 10 0 3 20 68 = ⋅ ⋅ = µ . C L SRF mH KHz pF L = ⋅ ⋅ = ⋅ ⋅ ≈ 1 1 2 1 68 2 170 13 2 2 ( ) ( ) π π C pF pF pF pF pF P = + + + = 5 5 13 8 31 T V pF mA ns ns T SPIKE BLANK MIN = ⋅ ⋅ + ≈ < 264 2 31 100 20 136 ( ) P mW SWITCH ≈ 125 P s V pF mA ns V V SWITCH ≈ ⋅ ⋅ + ⋅ ⋅ ( ) − 1 2 10 264 31 2 100 20 264 41 0 7 µ . D V V m = ⋅ ⋅ ≈ 0 71 41 0 7 264 0 16 . /( . ) . P mA A V mW COND = ⋅ ( ) ⋅ + ⋅ ⋅ ≈ 0 25 20 210 0 63 200 264 55 2 . . Ω µ P mW mW mW TOTAL = + = 125 55 180 Output Power = ⋅ = 41 20 820 V mA mW L V s mA mH 1 30 10 5 0 3 50 21 = ⋅ ⋅ = . . µ C L SRF mH KHz pF L = ⋅ ⋅ = ⋅ ⋅ ≈ 1 1 2 1 22 2 270 15 2 2 ( ) ( ) π π T V pF mA ns ns T SPIKE BLANK MIN = ⋅ ⋅ + ≈ < 135 2 35 100 35 100 ( ) C pF pF pF pF pF P = + + + = 5 5 13 8 31 F V V V s kHz S = ⋅ − ⋅ ⋅ = 135 2 30 0 7 135 2 10 78 / . µ |
Similar Part No. - HV9925 |
|
Similar Description - HV9925 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |