Thermal controller for electronic devices

An apparatus for controlling a temperature of a device under test, comprising:

• an adjustable first fluid source configured to input a cold fluid having a first temperature;
• an adjustable second fluid source configured to input a set point fluid having a second temperature that is substantially the same temperature of a set point temperature of the device and higher than the first temperature;
• an adjustable third fluid source configured to input a hot fluid having a third temperature higher than the first and second temperatures;
• a cold line that conveys the cold fluid from the adjustable first fluid source;
• a set point line that conveys the set point fluid from the adjustable second fluid source;
• a hot line that conveys the hot fluid from the adjustable third fluid source;
• a valve configured to discharge an adjustable amount of at least two of the cold fluid, the set point fluid, and the hot fluid into a combined fluid, the valve being located at a junction of the cold line, the set point line and the hot line;
• a heat sink configured to be in thermal contact with the device, wherein the combined fluid is discharged from the valve to the heat sink and circulates through the heat sink;
• a first fluid return line;
• and
• a second fluid return line,
• wherein an opening of the valve is controlled to discharge the adjustable amount of at least two of the cold fluid, set point fluid, and hot fluid such that a heat sink temperature compensates for changes in the device temperature and substantially maintains the set point temperature of the device, and
• after the combined fluid impinges on the heat sink, the valve discharges the combined fluid to the first fluid return line and the second fluid return line such that a portion of the combined fluid returns to the first fluid source via the first fluid return line, and a remaining portion of the combined fluid returns to the second fluid source via the second fluid line.