1. Programming Output Voltage (Selecting R1 and R2, as shown in Figure 1) Use the following formula to select the appropriate resistor values. VOUT = VREF (1 + R2 ) R1 where VREF = 1.23 V Select a value for R1 between 240Ω and 1.5kΩ. The lower resistor values minimize noise ...
Programming Output Voltage To select the right programming resistor R1 and R2 value (see Figure 1) use the following formula: 1. Programming Output Voltage (selecting R1 and R2) Select R1 and R2: ǒ Ǔ R2 1.0 ) V out + V ref R1 ǒ V out + 1.23 1.0 ) ǒ where Vref = 1.23 V ...
R2. The output voltage is given by the formula: FP= 1 / (2 xπx CFFx R1 // R2) VOUT= VADJx (1 + R1 / R2) As R1 reduces, the two equations come closer to being equal and the pole and zero begin to cancel each other out ...
1.ProgrammingOutputVoltage(SelectingR1andR2,1.ProgrammingOutputVoltage(SelectingR1andR2) asshowninFigure2)Usethefollowingformulatoselect theappropriateresistorvalues. R1canbween1kand5k.(Forbesttemperature R2=1k(8.13−1)=7.13k,closest1%valueis7.15k ...
电力电子课件lm2577t adj.pdf,L June 1999 M 1 5 7 7 / L LM1577/LM2577 Series M 2 5 SIMPLE SWITCHER® Step-Up Voltage Regulator 7 7 S General Description Features The LM1577/LM2577 are monolithic integrated circuits that n Requires few external components
+Vin +Vin Cin 100 mF R1 47 k 5 ON/OFF 3 +Vin R2 10 k Cin 100 mF 5 R3 47 k ON/OFF 3 GN D Z1 1N5242B Q1 2N3904 R1 10 k Vth ≈ 13 V NOTE: This picture does not show the complete circuit. Figure 28. Undervoltage Lockout Circuit for Buck Converter The following formula is...
1. Programming Output Voltage (Selecting R1 and R2, as shown in Figure 1. Use the following formula to select the appropriate resistor values. R2 = 1k (16.26 − 1) = 15.26k, closest 1% value is 15.4 kΩ. R2 = 15.4 kΩ. Select a value for R1 between 240Ω and 1.5 kΩ....
The formula that can be used to calculate the new value of R1 for a different output voltage is shown in Equation 2: VOUT = VADJ (R1/R2) + VADJ (2) Solved for R1: R1 = (VOUT - VADJ) / VADJ X R2 (3) The evaluation board is shipped with a 5.62 kΩ resistor installed at R...
The output voltage is given by the formula: VOUT = VADJ x (1 + R1 / R2) The value of resistor R2 must be 10k or less for proper operation. (1) EXTERNAL CAPACITORS To assure regulator stability, input and output capacitors are required as shown in the TYPICAL APPLICATION CIRCUIT. OUTPUT...
Figure 19. Setting Output Voltage The value of R2 should always be less than or equal to 10 kΩ for good loop compensation. R1 can be selected for a given VOUT using the following formula: VOUT = VADJ (1 + R1/R2) + IADJ (R1) where • VADJ is the adjust pin voltage • IADJ...