UBB1000

The UBB1000(CCI) is an interface chip for a contactless chipcard, see Fig.1. The UBB1000(CCI) converts the signals of a contactless energy- and data transmission to the requirements of chipcards with contacts. Such a chipcard typically contains a microcontroller and an EEPROM. The contactless transmission delivers the signals required by an ISO standard smart card microcontroller 83C852). The contactless energy- and data transmission is achieved by an inductive coupling between two coils in the terminal (transmitterlreceiver station) and two coils inside the chipcard. The chipcard coils are printed on a substrate foil. The CCl power is generated by the UBB1000(CCI) input rectifiers and voltage regulators. The bidirectional data transfer is achieved by a terminal phase modulation for data to the UBB1000(CCI) and a UBB1000(CCI) amplitude modulation for data to the terminal. A-B and C-D are used for the inductive energy- and data transmission. DT is the transmit data input (data from the chipcard to the terminal). DR is the data receive output (data from terminal). VP - VN provides a stabilized 5 supply for the UBB1000(CCI) load, e.g. for a microcontroller and an EEPROM. CLK is a clock signal with the transmission frequency, e.g. for the microcontroller. R and R- are reset signals, e.g. for a microcontroller.

The UBB1000(CCI) contains two bridge rectifiers, used as AC-DO converter. Two separate AC inputs A-B and C-D. Each input is provided with an input capacity (C1 respectively C2) to avoid spikes on the input voltage due to the diodes. One common DO output VP-VN1. The outputs of both bridge rectifiers are superimposed. VP-Vm is provided with a charging capacitor C3 to reduce the ripple voltage on VN, each input capacity consists of two capacitors in parallel to obtain symmetrical capacitances with respect to VN1 and VP. Each bridge rectifier consists of two bipolar diodes and two switched n-channel MOS transistors. The diodes are connected with their n-diliusion to the n-substrate and defined as VP.

Depending on the direction of the input current, one combination of a bipolar diode and a n-channel MOS transistor is conducting current. The peak-to-peak amplitude of the input voltages VAB respective VOL, is limited by the UBB1000(CCI) and depends on the data transmission from the UBB1000(CCI) to the terminal as shown in Table 1.