Question

Notify Me Bookmark

The following LED driver circuit is controlled by a 100 kΩ potentiometer connected to a 10 V supply and uses an LED with the following properties: Vf = 2.4 V for the LED when If = 20 mA. Find the following (I need exact values for these unless otherwise indicated): a. Maximum and minimum current through the LED based on potentiometer position. b. Maximum voltage across the LED. c. Minimum positive supply voltage needed by the op-amp to support the maximum current through the LED (rounded up to the nearest volt). d. Maximum power dissipated by the LED and the 10 Ω resistor.

The following LED driver circuit is controlled by a 100 kΩ potentiometer connected to a 10 V supply and uses an LED with the following properties: Vf = 2.4 V for the LED when If = 20 mA. Find the following (I need exact values for these unless otherwise indicated): a. Maximum and minimum current through the LED based on potentiometer position. b. Maximum voltage across the LED. c. Minimum positive supply voltage needed by the op-amp to support the maximum current through the LED (rounded up to the nearest volt). d. Maximum power dissipated by the LED and the 10 Ω resistor.

Image text
  1. The following LED driver circuit is controlled by a 100 k Ω potentiometer connected to a 10 V supply and uses an LED with the following properties: V f = 2.4 V for the LED when I f = 20 m A . Find the following (I need exact values for these unless otherwise indicated): a. Maximum and minimum current through the LED based on potentiometer position. b. Maximum voltage across the LED. c. Minimum positive supply voltage needed by the op-amp to support the maximum current through the LED (rounded up to the nearest volt). d. Maximum power dissipated by the LED and the 10 Ω resistor.

Detailed Answer

0 0

Please enter your email here. You will get email when this question is answered by our tutor.

Doubtrix Logo

Problem is not yet solved!

Click on Notify me to get email when question is answered.

Join Doubtrix with 7-days free trial

  • Icon Correct & Verified Answers
  • Icon No AI-Generated Answers
  • Icon Video Solution for Difficult Questions
  • Icon Work With Experts to Reach at Correct Answers
Notify me Login Sign Up

Similar/Related Questions

The amplifier circuit below uses an n channel FET with gm = 4.74 mS and ID0 = 4.53 mA. The resistor R1 = 2.38 kΩ and VDD = 20.7 V. a. Analyse the circuit to find an equation for the output voltage in terms of the input voltage. You do not need to submit this equation for this quiz, but you will need it to solve the following problems. (Hint: begin by using KVL to find an equation for vout in terms of iD and values we already know. Then write an equation for the FET that gives iD in terms of vGS. Combine these two equations to eliminate iD. ) ) In the following parts, give your answer to 3 siginficant figures as usual (except for part c), but keep intermediate results to more significant figures, otherwise rounding errors may lead to incorrect answers. b. What is the small signal gain of the amplifier (dvout dvin ) ? −11.3 c. What is the minimum output voltage of the circuit? (For this part only, give your answer to the nearest whole number. ) 0 V d. What is the (minimum) value of vin that corrsponds to the output voltage from part c)? Number V e. What is the maximum output voltage of the circuit? 20.7 V f. What is the (maximum) value of vin that corrsponds to the output voltage from part e)? Number Units

Solution
0 0

For the following two problems, the supply voltage VDD is 3.3 V, and the MOSFET transistors have VTH = 0.5 V, μnCox = 200 μA/V2, and λ = 0. (a) Design this common-source (CS) amplifier with the following constraints. That is, determine the W/L ratio for the MOSFET transistor (M1) and the resistance values for RD, RE, and R2. −RS = 200 Ω and R1 = 100 kΩThe amplifier must provide a small-signal gain ( = vout/vin) of 10. The maximum power budget is 5 mW. At DC, the voltage drop across RE is 0.5 V. The gate overdrive ( = VGS−VTH) of M1 is 0.2 V. (b) Now design this source-follower (SF) stage driving an 8 Ω speaker. RG is 100 kΩ. Determine the W/L ratio of the transistor M2 and the resistance value RS that bias the transistor at gm = 0.15 Ω−1 and ID = 30 mA. Also, calculate the small-signal gain (AVv = vout /vin ) of this SF stage driving the 8 Ω speaker.

Solution
0 0

For the circuit shown in Figure 1, NMOS device M1 has the following properties: kn’(W/L) = 180 μA/V2, VT0 = 2 V, λ = 0.02 V-1, γ = 0.4 V1/2, 2ϕF = 0.7 V, and ID = 10 mA. Note that capacitor Cbig is a DC blocking cap, i.e., Cbig is an open at DC and a short at all other frequencies. Figure 1. Circuit for Problem 1. a) Determine the numerical value of bias voltage Vbias which is needed to achieve a drain current of ID = 10 mA. b) Draw the small-signal equivalent circuit. c) Analyze the small-signal circuit to find Rin, Rout, and Av = Vout/Vin. Find the analytic expression for each quantity first, before determining the numerical answers. d) Recall that gmb/gm = χ. Determine the numerical value of χ for this problem. [Note that this part has nothing to do with parts (b) and (c).] e) What is the threshold voltage of device M1? [Note that this part has nothing to do with parts (b) and (c).] Show your work, list all numerical values in proper engineering notation format with appropriate units and with at least two decimal places of precision.
Solution
0 0