Summary of 1.2V-25V/10A Adjustable Power Supply Using Power Op-Amp
This article describes a compact power supply circuit utilizing the OPA549 power operational amplifier. It delivers an adjustable output voltage from 1.2V to 25V and supports a current limit ranging from 0A to 10A. The design features onboard trimmer potentiometers for manual adjustments, an LED indicator for thermal shutdown status, and screw terminals for connections. It requires a 30V DC input supply and a 5V logic supply, necessitating a large heat sink for full current operation.
Parts used in the Adjustable Power Supply:
- OPA549 power op-amp
- Two onboard trimmer potentiometers
- LED D1 over temperature indicator
- Screw terminals for input connections
- Screw terminals for output connections
- Large size heat sink
- Logic gate (for E/S pin indication)
This is a small size power supply based on OPA549 power op-amp that provides output voltage 1.2V to 25V with 0 to 10A adjustable current limit. Two onboard trimmer potentiometers provided to adjust the voltage and current, LED D1 is over temperature indicator. The circuit works with input supply of 30V DC and logic supply 5V DC. IC requires large size heat sink to work with full 10A current range.
Screw terminals for input and output connections are provided. The OPA549 is a low-cost, high-voltage/high-current operational amplifier ideal for driving a wide variety of loads. This laser-trimmed monolithic integrated circuit provides excellent low-level signal accuracy and high output voltage and current. The OPA549 operates from either single or dual supplies for design flexibility. The input common-mode range extends below the negative supply. The OPA549 is internally protected against over-temperature conditions and current overloads. In addition, the OPA549 provides an accurate, user-selected current limit. Unlike other designs which use a “power” resistor in series with the output current path, the OPA549 senses the load indirectly. This allows the current limit to be adjusted from 0A to 10A with a resistor/potentiometer, or controlled digitally with a voltage-out or current-out Digital-to-Analog Converter (DAC). The Enable/Status (E/S) pin provides two functions. It can be monitored to determine if the device is in thermal shutdown, and it can be forced low to disable the output stage and effectively disconnect the load. The OPA549 is available in an 11-lead power package. Its copper tab allows easy mounting to a heat sink for excellent thermal performance. Operation is specified over the extended industrial temperature range, –40°C to +85°C.
Features
- Input Supply 30V DC
- Logic Supply 5V DC
- Output 1.2V to 25V DC
- Load Current Limit Adjustable 0 To 10A
- Thermal Shutdown LED Indicator
A programmable source and sink power supply can easily be built using the OPA549. Both the output voltage and output current are user controlled. See Figure 12 for a circuit using potentiometers to adjust the output voltage and current while Figure 13 uses DACs (refer to datasheet). An LED connected to the E/S pin through a logic gate indicates if the OPA549 is in thermal shutdown.
Read more: 1.2V-25V/10A Adjustable Power Supply Using Power Op-Amp
- What is the output voltage range of this power supply?
The circuit provides an output voltage ranging from 1.2V to 25V. - How is the current limit adjusted on this project?
The current limit is adjustable from 0A to 10A using two onboard trimmer potentiometers or digitally with a DAC. - Can the OPA549 operate with single or dual supplies?
Yes, the OPA549 operates from either single or dual supplies for design flexibility. - Does the device have built-in protection against overheating?
Yes, the OPA549 is internally protected against over-temperature conditions and current overloads. - What are the required input supply voltages?
The circuit works with an input supply of 30V DC and a logic supply of 5V DC. - How can you tell if the device is in thermal shutdown?
An LED connected to the Enable/Status pin indicates if the OPA549 is in thermal shutdown. - Is it possible to control the current limit digitally?
Yes, the current limit can be controlled digitally with a voltage-out or current-out Digital-to-Analog Converter. - What package type does the OPA549 come in?
The OPA549 is available in an 11-lead power package with a copper tab for mounting.
