IC Controller for Switching Regulators: The functional block diagram of a MC34063 integrated circuit controller is shown in Fig. 17-38. This IC is designed to be used as a variable off time IC Controller for Switching Regulators. The components parts of the diagram in Fig. 17-38 are: Switching transistor (Q1) controlled by transistor Q2. Set-reset …
Step Up Converter or Boost Converter: A Step Up Converter, or boost converter, produces a dc output voltage higher than its supply voltage. In the circuit shown in Fig. 17-34(a), L1 is directly connected to the supply, and D1 is in series with L1 and C1 The collector of Q1 is connected to the junction …
Step Down Converter: A step-down switching regulator, or Step Down Converter (also termed a buck converter), produces a dc output voltage lower than its input voltage. The basic circuit arrangement for a step-down converter is shown in Fig. 17-30. Note the presence of the catch diode (D1). This is normally reverse biased when Q1 is …
Switching Regulator Operation: A Switching Regulator Operation can be thought of as similar to a linear regulator, but with the series-pass transistor operating as a switch that is either off, or switched on (in a saturated state). The output voltage from the switch is a pulse waveform which is smoothed into a dc voltage by …
IC Linear Voltage Regulators: 723 IC Regulator – The basic circuit of a 723 IC Linear Voltage Regulators in a dual-in-line package is shown in Fig. 17-20. This IC has a voltage reference source (D1), an error amplifier (A1), a series pass transistor (Q1), and a current limiting transistor (Q2), all contained in one small …
Op Amp Voltage Regulators: Voltage Follower Regulator – Refer once again to the Op Amp Voltage Regulators circuit in Fig. 17-11. The complete error amplifier has two input terminals at the bases of Q5 and Q6 and one output at the collector of Q2, Transistor Q6 base is an inverting input and Q5 base is …
Short Circuit Protection Circuit: Power supplies used in laboratories are subject to overloads and short circuits. Short Circuit Protection Circuit by means of current limiting circuits is necessary in such equipment to prevent the destruction of components when an overload occurs. Transistor Q7 and resistor R10 in Fig. 17-13(a) constitute a current limiting circuit. When …
Improving Regulator Performance: Error Amplifier Gain – The performance of a regulator is dependent on the voltage gain of the error amplifier. A higher gain amplifier gives better line and load regulation. So, anything that improves the amplifier voltage gain will improve the regulator performance. Two possibilities to increase Av are: using as transistor with …
Transistor Series Voltage Regulator: When a low power zener diode is used in the simple Transistor Series Voltage Regulator, the load current is limited by the maximum diode current. A high-power Zener used in such a circuit can supply higher levels of load current, but much power is wasted when the load is light. The …