HUMMER

      The features of HUMMER are 55°C to +125°C, 12 to 40 VDC input, Sync on HUM-70, Reduce hold-up capacitance by 80%, Powers DC/DC converterswith 28 Vin nominal, Hold-up time HUM-40 15 µs/µF HUM-70  8.6 µs/µF, Low power flag, Inhibit function. Interpoint's  Hold-Up Module Series provides a single product solution to the problem of maintaining electronic system operation during input power drop-out, typically reducing bulk capacitance requirements by more than 80%. The HUMMER module is compatible with the Interpoint DC/DC converters in Section B1 that have a 28 VDC nominal input and a high input line of 40 VDC.
      The traditional procedure for providing hold-up during power loss is to buffer the device HUMMER with enough bulk capacitance to allow a controlled shutdown to occur or an alternative power source to be brought on line. The problem with this approach is that very large capacitor banks are required because the capacitors are charged at the relatively low voltage at which power fails.
      The HUMMER Hold-Up Module provides an alternative with two important advantages: 1) it effectively reduces the low line voltage for normal DC/DC converter operation to 12 VDC thereby reducing power drop-out events, and 2) it charges hold-up capacitors to 40 volts, reducing the capacitance needed to produce a given hold-up time.
      The HUMMER module and two external components (a hold-up capacitor and a diode) are connected between the line source and the DC/DC converter as shown in Figure 3 (HUMMER Module System Block Diagram.) If an EMI filter is employed, the HUMMER module is connected between the filter and the converter). The module first charges the external capacitor to 40 volts, and then allows the converter to operate off the line voltage. When the line voltage drops to between 12 to 18 VDC, a boost converter in the module supplies an output at the capacitor charging voltage (40 VDC). If power fails (the input voltage drops below 12 VDC), the converter is powered from the external hold-up capacitor.