安森美电源管理芯片ncp1652设计帮助

When selecting values use low line, full
T
Cout
CT FB
Out A
Out B Rupper
delay
ISpos Rlower RISpos
RISpos
I
Vramp @
Notes: The location codes at the top of each column, corespond to the letters on the schematic located below the table. Inputs are color coded to data. If some data exceeds the design limits, the like color values should be changed. Rs affects all columns. Cell contents in Bold Red indicate that the signal exceeds the design limits. Change the appropriate parameters to assure that all signals are in an active region. When selecting values use low line, full load conditions.
ISpos Rlower RISpos
GND RAMP COMP
IAVG CIAVG RIAVG
RRC
GND RAMP COMP
RISpos IAVG CIAVG RIAVG
RRC
Description of signals A B C D E F G H Peak Shunt Voltage - The instantaneous current signal developed across the current shunt. This is a positive going signal. Isenseout peak - The high frequency current signal out of the current sense amplifier output that is summed with the ac error signal and the ramp compensation signal to provide the input to the PWM. Isenseout avg - The low frequency current signals out of the current sense amplifier. Both currents will be equal, but will result in different voltages. Ac Amplifier, Inverting Input - The voltage signal that results at the inverting input of the ac error amplifier. This signal is the sum of the current sense amplifier output current and the output of the Average Current Compensation amplifier. Feedback input - Error signal from secondary side regulator. This signal is converted into a current in the V-I converter, which has a 1 volt offset. Ac Error Amplifier Output - The voltage output of the ac error amplifier which is required to generate the proper current out of it's buffer. Ac Error Amplifier Output Buffer - This is the current required out of the ac error amplifier buffer, to sum to 4 volts when added to the current and ramp signals (H). Ramp Voltage at Turn Off - The peak ramp compensation voltage is calculated to the right of R 13, once a value is entered. This is the voltage of the ramp compensation signal at the time when the power switch is shut off. This signal is added to the peak current and the ac error amp signal to determine when the switch cycle is terminated. Peak Current + Ramp - This is the sum of the peak switch current (B) when fed into a 16 kOhm resistor, and the instantaneous ramp voltage (H).
G H Vout I out ac e/a ac e/a buffer (uA) 2.54 27.9 2.49 33.7 2.48 34.7 2.50 32.1 2.55 27.1 2.60 21.1 2.66 15.0 2.71 10.0 2.74 6.6 2.75 5.5 2.74 6.6 2.71 10.0 2.66 15.0 2.60 21.1 2.55 27.1 2.50 32.1 2.48 34.7 2.49 33.7 2.54 28.5 0.75 0 2.80 300
NCP1652 Design Spread Sheet Provided by ON Semiconductor Po = Vo = Vin = Lp = Np/Ns= Pin = 90 19.5 90 600 8 102 W W us V V uH T = 14.286
Suggested
VFFscale acscale RISPOS = RRC= RIAVG =
CM From Soft Skip
Out A
Reference Generator
AC IN VFF AC COMP
D D
G
H
+4.0 V
PWM Logic and Driver
Out B Rupper
Rdelay
Rcomp RVFF2 Ramp Com tLEB
I
Rac2
CM
Ccomp
B
Current Sense Amplifer
0.012 0wk.baidu.com131 27 99,576
Loc. time (deg) 1 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 179 Min Max
A Pk shunt voltage 0.005 0.055 0.111 0.167 0.221 0.271 0.314 0.347 0.368 0.375 0.368 0.347 0.314 0.271 0.221 0.167 0.111 0.055 0.005 0.000 0.750
D B Mult Out(V) Isenseout Pos in peak (uA) 0.07 1.4 0.70 13.7 1.37 27.7 2.01 41.7 2.58 55.3 3.08 67.9 3.48 78.6 3.77 86.8 3.96 92.0 4.02 93.8 3.96 92.0 3.77 86.8 3.48 78.6 3.08 67.9 2.58 55.3 2.01 41.7 1.37 27.7 0.70 13.7 0.07 1.4 0 300
Inputs are color coded to data. If some data exceeds the design limits, the like color values should be changed.
Cell contents in Bold Red indicate that the signal exceeds the design limits. Change the appropriate parameters to assure that all signals are in an active
6.5 V
Vcc UVLO Latch
R
SE T
6.7 k
FB
F
Overload Detect
+
Vcc Mangment
-
150 ms timer and logic
Soft Skip Logic
Q
+5.0 V
S
CL R
Q
LATCH -OFF
Latchoff
OSC Jitter
CT
Cout
CT FB
I
Suggested Range 700 to 1000 700 to 1000
kOhms kOhms
acscale = RVFF2 / (RVFF1 + RVFF2) acscale = Rac2 / (Rac1 + Rac2)
The location codes at the top of each column, corespond to the letters on the schematic located below the table.
0.01 Voltage FF divider ration 0.01 divider ratio 0.1 Current sense shunt 30 (kOhms) ramp comp 100,000 Current scaling resistor (Ohms) 3.40 Vpk
Suggested Range 0.01 RVFF1 Rac2
turn-off 3.37 2.98 2.66 2.41 2.23 2.09 1.99 1.92 1.89 1.87 1.89 1.92 1.99 2.09 2.23 2.41 2.66 2.98 3.35 0.00 4.00
Rac1
RVFF1
Rac1
RVFF1
Vcc
Start-Up
Reference
D ac amp invert in 0.07 0.70 1.37 2.01 2.58 3.08 3.48 3.77 3.96 4.02 3.96 3.77 3.48 3.08 2.58 2.01 1.37 0.70 0.07 0.00 4.50
E F Ref mult FB input Iin (uA) voltage 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 75 3.771 0 1.5 900 4.5