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Describes the TC120 DC/DC Power Converter, its capabilities, and features.
Details electrical, physical, and qualification attributes of the TC120 converter.
Discusses cooling requirements and methods for the TC120 converter.
Provides guidance on selecting optimal installation locations, considering environmental factors.
Offers advice on proper cable routing to avoid damage and interference.
Outlines limitations related to TSO approval and aircraft installation.
Explains the nameplate and modification (MOD) status identification for the unit.
Provides overview of installation, including unit versions and interconnect diagrams.
Details procedures for unpacking and inspecting the TC120 converter and its components.
Covers the construction of the cable harness and wire gauge selection.
Details the pin assignments for the unit's connector for DC input, output, and enable.
Describes how to adjust the output voltage using the trimmer and the required tools.
Provides instructions for mounting the TC120 converter using the specified mounting holes.
Warns against connecting the converter output to another power source to prevent damage.
Details final checks, including output verification and functionality testing.
Explains the TC120's design as a high-efficiency switch-mode power supply.
Details current limits based on output voltage and connector capabilities.
Covers various protective features of the TC120 converter.
Explains the remote ON/OFF feature for controlling the unit's output.
Discusses the operating input voltage range and temporary operation conditions.
Details the unit's response to input voltages exceeding 34VDC.
Specifies the adjustable output voltage range and contact for non-standard ranges.
Describes the internal temperature sense device and automatic shutdown protection.
Explains the TC120's short circuit capability and recommended output protection.
States that no periodic maintenance is required for continued airworthiness.
Lists the environmental qualification tests and categories the TC120 meets.
The TC120 DC/DC Power Converter is a lightweight and efficient power conversion solution designed for a wide range of aviation applications. Its primary function is to translate a direct current (DC) input of 28 volts into an adjustable DC output ranging from 5 to 18 volts. This makes it suitable for powering various avionics, instrumentation, personal charging devices, lighting, and other electrical systems commonly found in general, business, and commercial aircraft. The unit is engineered to provide a nominal output of 120 watts, ensuring ample power for connected devices.
One of the key usage features of the TC120 is its remarkable installation flexibility. It can be mounted both inside and outside the pressure vessel of an aircraft, eliminating the need for strict temperature control. This adaptability is due to its robust design, which includes resistance to extreme altitudes, temperatures, and high levels of condensing humidity. The unit's small size and light weight, at only 11.0 oz (312 g), further enhance its versatility, allowing for more flexible installation locations compared to other certified solutions in the aviation market. The TC120 does not require external cooling or internal active cooling mechanisms like fans, as it dissipates heat passively through conduction via its aluminum case and base, or through radiated cooling. While not strictly required for rated performance, mounting the unit to a thermally conductive metal surface can help prevent potential overheating and extend its lifespan, especially when operating at full power or under overload conditions. The unit can be mounted in any orientation, but it's important to allow sufficient clearance for the mating connector and back shell access, which may require up to five inches of space.
The TC120 also incorporates several protective features to ensure reliable and safe operation. These include short circuit protection, overload capability, low input voltage shut-down, temperature monitoring, and reverse polarity protection. A self-resettable over-temperature disable mechanism automatically shuts down the output if internal temperatures exceed maximum ratings and resumes normal operation once the temperature returns to acceptable limits, without requiring external intervention. The unit can withstand continuous short-circuit operation without damage. For installations where high currents in a short-circuit fault condition are undesirable, the use of a circuit breaker on the TC120 output is recommended.
An optional remote enable (on/off) feature is available with the 6430120-2 version of the TC120. This allows users to remotely enable or disable the unit's output by providing a ground signal to a specific pin, typically via a remote-mounted switch. This feature adds convenience and control to the power management system. The output voltage of the converter is adjustable between 5 and 18 VDC. The default output voltage is factory-set to approximately 13.8V. Users can adjust this voltage while the TC120 is connected to the mating harness and aircraft power, but disconnected from the output load. A multi-meter should be used at the load end of the harness to measure the output voltage during adjustment. The adjustment trimmer is accessed by removing a 4-40 screw near the label, and a 2mm flat blade screwdriver can be used to turn the trimmer clockwise to increase voltage or counter-clockwise to decrease it.
The TC120 is designed as a high-efficiency, non-isolated, buck topology, solid-state switch-mode power supply. Its Pulse-Width-Modulation (PWM) circuits utilize current-mode control technology, operating at high frequencies and providing pulse-by-pulse protection for internal power devices against excessive current. The continuous rated output current and power of the TC120 are dependent on the user-selected output voltage. While rated for 120 watts, if the output voltage is below 9 VDC, the continuous rated output current is limited by the typical maximum current capacity of the MIL 510514-5P connector and its mating harness. The unit is capable of exceeding its continuous rated current for short periods (up to 2 hours) to accommodate surge and fault conditions, allowing it to trip slow-acting thermal circuit breakers without degradation. When installing, it's crucial to consider the allowable voltage drop from wire length between the TC120 and the load, especially for high-current applications, as connector current ratings are also dependent on wire size.
The TC120's input voltage range is nominally 24-32VDC, with qualification testing performed from 22 to 34 VDC. It can temporarily operate at lower voltages for start-up and emergency conditions. However, in the temporary operating range, the TC120 cannot boost the input voltage to produce a higher output voltage. For example, if the output voltage is set to 18 Volts and the input voltage drops below 19 Volts, the output voltage will begin to fall off, approximately 1 Volt less than the input voltage. If the input voltage exceeds 34VDC, the unit senses an over-voltage condition and disables the output, resuming normal operation once the input voltage drops below 34VDC. The actual adjustment range of the trimmer typically extends from 4.3 to 18.4 VDC.
Regarding maintenance features, the TC120 DC/DC Converter is designed for minimal upkeep. No periodic scheduled maintenance or calibration is necessary for its continued airworthiness. In the event that the unit fails to perform to its specifications, it must be removed from the aircraft and serviced by Mid-Continent Instruments and Avionics or their authorized designees. This simplifies long-term ownership and reduces operational costs associated with routine servicing. Prior to operating the unit in the aircraft, it is recommended to verify its output and functionality. To prevent accidental damage to other systems, the output should not be attached to other equipment or power busses before verification. A multi-meter should be used at the terminating end of the cable to ensure proper voltage and polarity. Once verified, the installation can be completed, and the functionality of the remote on/off feature (if used) should be checked. The product's nameplate identifies the manufacturer, part number, description, certifications, and technical specifications, including a "MOD" or modification number that indicates notable changes in the hardware design. Details on specific changes associated with each MOD status are available in the product's published Service Bulletins.
General| Output Voltage | 12 VDC |
|---|---|
| Output Current | 10 A |
| Output Power | 120 W |
| Efficiency | >90% |
| Operating Temperature | +70°C |
| Protections | Overvoltage, Reverse Polarity, Overcurrent |
| Category | Converter |
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