Monolithic three-terminal linear voltage regulators appeared nearly two decades ago, which are simple to use & not expensive. So these regulators quickly eclipsed discrete and previous monolithic building blocks to dominate the market. LT1070 IC is a high power switching regulator manufactured previously by Linear Technology but acquired by Analog Devices Inc. While designing any circuit with this IC, some important things need to be considered like layout, power supply decoupling, environmental and temperature considerations: Thus, this article provides brief information on a high power, low cost and high efficiency based switching regulator like LT1070 IC, pin-out, features, specifications, and its applications.
What is LT1070 IC?
The LT1070 is a monolithic high-power switching regulator that is available in a five-pin T0-220 (or) TO-3 power package. This IC can operate in standard switching configurations like; flyback, buck, forward, boost, Cuk, and inverting.
This IC has a high efficiency and high current switch on the die alongside oscillator control & protection circuitry. So, the addition of all functions permits this IC to be designed in a standard that makes it very easy to utilize and gives “bust proof” operation related to that attained with three-pin linear regulators.
The LT1070 IC has many unique features which utilize an adaptive antisat switch drive to permit extremely wide-ranging load currents without loss within efficiency. So it is externally activated shutdown mode decreases the whole current supply to 50µA for standby operation. By utilizing the optional flyback regulation mode of the IC, completely isolated & regulated outputs can be produced without the requirement for optocouplers (or) additional transformer windings.
LT1070 IC Working Principle
The LT1070 IC operates with a voltage supply that ranges from 3Volts to 60Volts that draws 6mA quiescent current only. These ICs deliver up to 100 watts of load power without external power devices. So they provide outstanding AC load, DC load & line regulation by using current mode switching methods.
Thus, the LT1070 IC works by simply comparing the voltage supply at the feedback pin to an inside reference, controlling the current & duty cycle of the VSW pin of the IC. This IC has high efficiency, high load power, shutdown mode, flyback regulation mode, low quiescent current, AC load, DC load, and line regulation which makes it easy to utilize & provides bust-proof operation.
LT1070 IC Pin Configuration:
The LT1070 IC pin configuration is shown below. So this IC includes 5 pins which are discussed below.
LT1070 IC Pin Configuration
- Pin-1 (VC): It is a voltage compensation pin which is the main connection point for a voltage-controlled current source & current sink.
- Pin-2 (FB): It is a feedback pin which is the input supply for the feedback signal which is used for voltage regulation.
- Pin-3 (GND): It is the ground pin of IC.
- Pin-4 (VSW): It is an output or switching mode pin.
- Pin-5 (VIN): It is an input supply pin of IC.
Features & Specifications:
The features and specifications of LT1070 IC include the following.
- LT1070 is a 5-pin monolithic high-power switching regulator.
- It is available in T0-220 (or) TO-3 power package.
- It has wide input voltage ranges from 3V to 60V.
- The low quiescent current is 6mA.
- It has an internal 5Amps switch.
- This IC uses very less external components.
- Its shutdown mode draws 50µA current supply only.
- The flyback-regulated mode includes completely floating outputs.
- Its operating temperature ranges from 0°C to 100°C for commercial,– 65°C to 150°C for storage, and – 40°C to 125°C for industrial.
- The lead temperature for soldering for 10 seconds is 300°C.
Equivalents & Alternatives
The equivalent LT1070 ICs from the same family are LT1071HV or LT1070HV. Thus, alternative LT1070 ICs are; LM2596, MC34063, XL6009, MP9486, TPS54231, MP1584, LM2576, TPS5430, CS1411, NCP3170, LT1765, RT8059, LT1370, etc.
15Volts to 100Volts Converter Circuit with LT1070 IC
The 15Volts to 100Volts converter circuit with LT1070 IC is shown below. So this circuit converts 15Volts input voltage to 100Volts output voltage at 300mA current. The required components to make this circuit mainly include; LT1070 IC, diodes, resistors like 1.24K, 10K, 98K, 680 Ohms, capacitors like 200uF, 0.047uF, and 0.68uF, 4mH inductor.
Connections
The input supply provided to the VIN pin of the IC in this circuit is 15V, the switching pin of this IC is connected to the L1 inductor. Here, the feedback pin of the IC monitors the o/p voltage throughout the voltage divider. So the inductor in this circuit works through the LT1070 IC to store energy whenever the switch in the LT1070 IC is ON and produces energy to increase the voltage whenever the switch is OFF.
Here D1 Diode in the circuit rectifies the increased voltage from the inductor & allows it to supply to the C1 output capacitor. So the C1, C2 & C3 capacitors are used to filter, stabilize & smooth the rectified o/p voltage. Thus, the R1 & R2 resistors form a voltage divider network that provides feedback to the IC to control the output voltage.
15Volts to 100Volts Converter Circuit with LT1070 IC
Working
Whenever the power supply is provided to the circuit, the LT1070 IC will start switching. So the inside switch of this switch turns ON & OFF to cause current to supply throughout the L1 inductor. Whenever the switch is turned ON, the current supplies throughout the L1 inductor and stores energy within its magnetic field.
Once the switch is turned off, the magnetic field within L1 fails then the stored energy will be released. So this causes the voltage to increase significantly and it will be rectified through the D1 diode. This rectified high voltage can be stored within the C1 output capacitor and it smooths the output voltage to provide a stable 100V DC voltage.
Thus this output voltage can be sensed by the R1 & R2 voltage divider network and fed back toward the FB pin of the IC. This IC corrects its duty cycle to maintain the preferred 100V output voltage. Here, a snubber network can be formed with C3, D2, and R4 which protects the inside switch of the IC from voltage spikes produced whenever the magnetic field of the inductor collapses.
Advantages & Disadvantages
The advantages of LT1070 IC include the following.
- The LT1070 monolithic switching regulator has wide input voltage ranges from 3Volts to 60Volts.
- This IC draws a 6mA quiescent current only.
- It is a self-protected IC.
- This IC can be synchronized externally.
- It is self-protected from overloads.
- It operates almost in all switching topologies.
This IC has an externally triggered shutdown mode that decreases the total current supply to 50µAmps. - It is easy to use and economical.
- This IC has an immediate response to i/p voltage differences.
- They provide outstanding AC, DC load & line regulation by using current mode switching methods.
- This IC doesn’t need broad switching regulator design knowledge.
- It can be utilized in all standard switching designs.
The disadvantages of LT1070 IC include the following.
- These ICs generate noise.
- High-frequency switching regulators decrease efficiency, thus it shortens battery life & enhances operating temperatures.
- These are more expensive as compared to linear regulators.
- They need more passive components, magnetic parts, and semiconductors which can make them very complicated to design.
- Compliance through EMI regulations can be labor-intensive and time-consuming.
Applications
The applications of LT1070 IC include the following.
- LT1070 IC can be utilized as a power inverter mainly for positive (+) to negative (or) negative (-) to positive.
- This IC can be utilized as a battery-up converter and an off-line converter equal to 200 watts.
- This switching regulator can be utilized as a boost converter from 5Volts to 12Volts, local logic supplies, and a battery charger.
- This IC is used in Battery chargers, Offline power supplies, local logic supplies, driving high voltage FET, voltage boost converters, etc.
Please refer to this link for the LT1070 IC Datasheet.
Thus, this is an overview of LT1070 IC is a high-efficiency switching regulator with a wide range of input voltage & flexible configuration choices. So this IC has some features like frequency compensation, an internal oscillator & protection features which include thermal shutdown and current limiting. Thus this IC is reliable and flexible which makes it a popular choice mainly for a broad range of power supply designs like automotive and industrial, buck, boost & inverting applications to provide up to 5Amps output current. Here is a question for you, what is LT1071 IC?