- Question 100 Marks In The Assignment I You Analyzed And Designed The Charge Readout Circuit For Pzt Actuator Shown In F 1 (116.24 KiB) Viewed 23 times
Question 100 Marks In the assignment I, you analyzed and designed the charge readout circuit for PZT actuator shown in Fig 1(a). One of the problems that is encountered in the readout circuit is that the last stage of the amplifier, which is the non-inverting amplifier, amplifies low-frequency noise from power supply or the vibration of the actuator due to environmental factors. It also amplifies any of DC imperfections contributed from the previous stages. Reducing the noise at the output is important while ensuring the readout signal is amplified. Although there are other modifications that may be applied to the non-inverting amplifier in order to achieve high signal- to-noise ratio, the non-inverting amplifier will be replaced by a three-stage transistor amplifier shown in Fig. 2(a) in this assignment. Your task will be to analyze the amplifier by calculating its gain, input and output impedance, and bandwidth. Vin R₁ ww M1 Q2 Q3 R₂ K₁ = 10mA/V² B=150 B-80 +V VIZT CPZT HHO PZT Actuator Transistor Parameters VTN = -2V VA = 80V VA = 60V C₂ λ=0.02V-¹ VBE = 0.7V VBE = 0.7V www R5 Fig. 1: PZT actuator self-sensing readout circuit The three-stage amplifier consists of one n-channel MOSFET transistor M1 in depletion mode with W/L = 1 and two BJT transistors Q1 and Q2. The transistors have the model parameters as provided in the table below +V کے R3 www +V Cgs = 3.5pf, Cgd = 0.1pf fT2GHz, Cu= 0.2pf fT2GHz, Cu= 0.2pf -Vo
R₁ 10K C₁ 10μF RG 1M Vs Roz 0.62K R$1 0.2K M₁ R₁ 78K C₂ C3 10μF R₂ 22K www RE2 10μF 1.6K Rc₂ 4.7K R3 91K Q2 C5 10μF R4 120K -C4 10μF www Q3 RE3 3.3K Fig. 2: A three-stage transistor amplifier +15V C, 10μF RL 0.25K
PART II (Q-point and transistor model parameter calculations) a) [P] Draw the DC equivalent circuit of the transistor amplifier in Fig. 2. Note that capacitors act as open circuit in DC conditions. [5 marks] b) [P,C]Show that the Q-Point values are: M1( ID=5mA, VDs-10.9V), Q1 (Ic=1.57mA, VCE 5.09V), and Q2 (1.99mA, 8.36V). [12 marks] c) [P,C] Calculate the transistor model parameters for each transistor, namely gmi, gm2, gm3, fol, 102, 103, rz2 and rx3 [16 Marks] d) [D] *Comment on the possible range of resistance values that may replace the Rc2 = 4.7KQ, RD2 = 0.62KS of the BJT Q1 transistor in the amplifier. [Hint: BJT must operate in a forward-active region and MOSFET must operate in a saturation region [12 Marks]