Figure 9. Circuit with the simplifications of Figures 7 and 8.
Actual ValuesBy plugging in some actual values for R1, R3, R4, and R5, we can compare the resultant bandwidth to that achieved for the circuit of Figure 1, and thus quantify the effect of R4 and R5 on the circuit performance.
Using the equations in Figure 9, we can come up with values for R1, R3, R4, and R5,http://www.siyinzg.com/功率电感 and can then calculate the resultant bandwidths.
Using a spreadsheet, one can find component values that satisfy the equations in Figure 9: (6) R1 = 3.48kΩ, R2 = 10kΩ, R3 = 4.53kΩ, R4 = 1kΩ, and R5 = 2.8kΩ. These component values result in the bandwidths listed in Table 2. Note these results show a greater than a 100 times improvement from the circuit of Figure 1, whose data are listed in Table 1!!
Table 2. Bandwidth of the circuit of Figure 6, with Resistance Values of Equation 6. ConditionCwiper = 10pF*-0.1dB bandwidth-0.5dB bandwidth-3dB BandwidthPot at 0 Code4.1MHz9.3MHz26.3MHzPot at Mid Scale4MHz8.9MHz25.1MHzPot at Full Scale4.3MHz9.6MHz27.3MHz*Note the bandwidth scales inversely with wiper capacitance. For example, with a 3pF Cwiper, the bandwidths will be at a 3.3x higher frequency (i.e. 10/3).
SummaryThis article has shown how by simply adding a few resistors in parallel with a relatively low bandwidth digital potentiometer the resulting bandwidth can be increased by a factor of 100, a significant improvement. This assumes that the applications can tolerate the reduced control range necessary for the improvement. The increased bandwidth can enable the use of digital pots for high frequency applications, previously not considered, such as video signal path control. SPI is a trademark of Motorola, Inc. DS1267±5V、双路、数字电位器芯片(, 328kB)
DS1669Dallastat数字电位器(, 180kB)
DS1803可编址、双路数字电位器(, 304kB)
DS1805可编址数字电位器(, 260kB)
DS1806六路、数字电位器(, 296kB)
本人用IRS2110 HO 端始输出奇怪的波形本人买的是IRS2110 （和IR2110不一样吗），LO一直可以输出，HO 输出一个很乱的波。于是我把自举二极管拿了。发现VS脚还会输出一个矩形不规则波（并没有给VS脚通电）
怎么个
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