安森美电源管理芯片ncp1652设计帮助

1、ncp1652 design sheet directions this spreadsheet calculates both system and bias component data for use with the ncp1652. system calculations include duty cycle, peak switch voltage, peak switch current and capacitor ripple currents. this information is valuable when choosing components for the powe

2、r path. values for all bias components for the chip will be chosen with user input. inputs: all inputs are located on the main sheet (e.g. step 1, not 1a) and have light violet backgrounds. all other cells are protected against inadvertent changes. begin your design with step1 and work your way thro

3、ugh all the steps, going from top to bottom in all the sheets. values should be entered in the order in which they occur. in some cases this program will suggest values. you may enter any value that you wish, but in general, it is advised to enter the nearest standard value. intermediate steps label

4、ed #a provide additional information to the user but are not necessary to fill out to complete the design. these sheets are protected against changes in most cells, except where inputs are allowed. this has been done to assure the integrity of this spread sheet. it can not be modified by the user. a

5、ny comments or suggestions regarding changes in this document should be sent to . system input (step1) this sheet allows system variables, such as inductance, frequency and voltage ranges to be input and analyzed. the subsequent spreadsheets will require this data to properly bias the ncp1652. the d

6、ata for the graphs on this sheet are available on the sheet titled 1a. sample for system input (step1) the design constraints design constraints section is for minimum pomax=90 wmaximum system power and maximum system vinmax=265 vrmsmaximum line voltage data. most parameters vinmin=85 vrmsminimum li

7、ne voltage (other than l) should be vo =19.5 vnominal output voltage known at the outset. lp =500 uhnominal primary inductance typically, design constraints fswitch =100 khzdesired switching frequency should not change for a np/ns=4turns ratio (does not have to be an integer) given design. peak swit

8、ch voltage is approximately (v).495.5 peak switch voltage includes approximation for spikes. actual values should be measured the design variables section allows the unit design variablesnote: evaluation parameters will turn red if out of limit range. to be analyzed under a pout =100 woutput power f

9、or evaluation of peak current, duty cycle, ripple, etc. specific set of line and vi =85 vinput voltage for evaluation load conditions, and effic =0.8system efficiency (typically .80 to .90) will not affect the design fline = 60 hzinput line frequency values of the elements. it is recommended t =10 u

10、scalculated input switching period to set the design pin =125 wcalculated input power variables to full load and low line to select all components. once component selection is complete, these data may be changed to evaluate parameters over various line and load conditions. graphical data: this sprea

11、dsheet is designed to show data in a graphical format. this requires some amount of estimation by the user to determine the values shown. the calculations sheet contains all of the data shown if exact values are necessary. an alternate method, is simply to point the cursor at a point on the curve an

12、d hold it there for several seconds. the x and y values of that point will be displayed in a box near the cursor. output voltage: the output voltage for the ncp1652 based system is not theoretically constrained due to the presence of the transformer. practically, however, the output voltage will be

13、in the range of 12 v to about 400 v. at the lower end, energy storage requirements get very high at lower voltages and at or above 400 v, a regular boost converter is more applicable. peak current: the peak current that the switch will see is an important parameter. it affects both the current limit

14、 setting, as well as the rating of the power switch. to see the effect of the input voltage and inductance on this parameter, enter the conditions for low line and full load. as the inductance value is varied the change in peak current can easily be seen. inductance: there is a trade-off in choosing

15、 the primary inductance (a low value leads to smaller transformer size but higher peak currents and a high value leads to lower peak currents but larger transformer). if the load is greater than several hundred watts, it is normally desirable to operate in continuous conduction mode. the peak and av

16、erage current chart, the di/dt plot, and the cont/discont. load =90 watts primary switching current vs. phase angle0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 phase angle (degrees) current (amps) peak currentpedestal currentaverage current duty cycle & cont/discont0% 25% 50% 75% 10

17、0% degrees duty cycle (%) duty cycle mode 100% = discontinuous 50% = continuous provided by on semiconductor vdsdpwronpwrswonpwrswoffpwrtotalpavgirms1 irms1-sq irms2pcond (volts)(watts)(watts)(watts)(watts)(watts)(amps)(amps)(watts) 1580.990.00.000.010.011.090.030.001.470.62 1780.880.00.010.060.091.

18、090.320.10 2000.780.10.040.130.281.090.660.430.60 2200.710.30.080.220.561.090.990.98 2380.660.50.130.310.921.091.311.72 2530.620.70.190.411.321.091.602.57 2660.591.00.250.501.711.091.853.42 2760.571.20.310.572.041.092.044.15 2810.551.30.340.622.261.092.154.64 2830.551.40.350.632.341.092.194.82 2810.

19、551.30.340.622.261.092.154.64 2760.571.20.310.572.041.092.044.15 2660.591.00.250.501.711.091.853.42 2530.620.70.190.411.321.091.602.57 2380.660.50.130.310.921.091.311.72 2200.710.30.080.220.561.090.990.98 2000.780.10.040.130.281.090.660.43 1780.880.00.010.060.091.090.320.10 1580.990.00.000.010.011.0

20、90.030.00 ifwddtrrirevpdiss (cond)pdiss (recov)pdiss (tot)pavgirmsirms1-sqirms2 (amps)(ns)(amps)(watts)(watts)(watts)(watts)(amps)(amps) 0.230.0138.10.270.000.010.014.450.03050.009.82 2.550.1257.53.060.200.120.324.45 0.9728090.952.22 5.620.2263.96.750.830.291.124.45 2.7679587.66 9.050.2967.710.861.840.502.354.45 5.05089725.51 12.600.3470.415.113.130.733.864.457.5873157.57 16.000.3872.319.204.540.955.494.45 10.13155102.65 19.000.41