Customer pole display and interface

This application claims the benefit of U.S. Provisional Application No. 60/592,783 filed on Jul. 30, 2004, the disclosure of which is incorporated herein by reference.

A portion of the disclosure of this document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction of the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever.

1. Field of the Invention

The present invention generally relates to customer pole displays which are referred to as point-of sale pole displays or pole displays, commonly used in Point-of-Sale (POS) systems, and more particularly to providing power to point-of sale pole displays without requiring connection to an alternating current power source.

2. Background of the Related Art

A customer pole display is a common peripheral device used with most point-of-sale (POS) terminals. A major function of the pole display is to show the customer retail transaction information, such as an identification or description of the item being purchased, the quantity being purchased, the corresponding unit price, the total price, and the like. In many states, the inclusion of a pole display in a POS terminal is required by law.

The current most popular method to interface a pole display to a computer, in cases where the POS application software is installed, is through an RS232 port. FIG. 1 shows a conventional pole display assembly 10 with an RS232 interface connector 12 . However, since the RS232 interface does not provide sufficient power to energize a pole display, a power adaptor 14 is required to step down the 120VAC or 240VAC power obtained from a standard electrical outlet to about 7VAC, which is then rectified and regulated in the pole display assembly 10 to 5VDC. The power adaptor is shown as being attached to a pigtail cable connected to the RS232 interface connector 12 .

FIG. 2 shows a block diagram of the conventional pole display assembly 10 with RS232 interface shown pictorially in FIG. 1 . Display data and commands from the POS computer terminal enter into the pole display assembly 10 through the RS232 interface connector and an RS232 interface circuit 16 . A microcontroller 18 processes the data and commands from the RS232 interface circuit 16 and transmits this information to a vacuum fluorescent display (VFD) 20 to illuminate appropriately addressed display pixels.

Most commercially available VFDs require two special voltages; approximately 4.7VAC for filament power and approximately 40VDC for anode power. These two voltages are ordinarily generated by a DC-DC converter 22 . As indicated above, the primary source of power for the pole display assembly 10 is conventionally derived from the AC power line connected to the power adapter 14 . The power adapter 14 steps down the line voltage to approximately 7VAC and an AC rectifier and voltage regulator 22 converts the 7VAC voltage to a stable 5VDC voltage, which is used to power the RS232 interface 16 , microcontroller 18 , and DC-DC converter 24 . However, the array of peripheral connectors and electronics is costly, cumbersome, difficult to assemble, and subject to failure.

Thus, there is a need in the field of POS computer terminals for an alternative that would alleviate the need for a pigtailed external power adapter that reliably converts 120VAC power to the voltages required by the pole display assembly associated with a POS computer terminal and the corresponding peripheral components and electronics.

These and other goals, purposes, and objectives are met by the present invention, which provides a method of using a customer display, also referred to as point-of-sale pole display or pole display, including connecting a Universal Serial Bus to a point-of-sale display, inputting a power signal from the Universal Serial Bus, translating the power signal input from the Universal Serial Bus to a display power signal, and connecting the display power signal to the point-of-sale display. The display power signal is adapted to provide power to the point-of-sale display

A Universal Serial Bus-compatible interface adapted to provide power to a point-of-sale display is also provided, which includes a connector adapted to be coupled to a Universal Serial Bus, and a converter operatively coupled to the connector and adapted to translate a power signal input from the Universal Serial Bus to a display power signal. A point-of-sale display assembly is provided, which includes a display, a connector adapted to be coupled to a Universal Serial Bus, and a converter operatively coupled to the connector and adapted to translate a power signal input from the Universal Serial Bus to a display power signal.

These and other objectives, features, and advantages of this invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.

FIG. 1 is a pictorial view of a conventional point-of-sale pole display and interface.

FIG. 2 is a block diagram of the conventional point-of-sale pole display and interface shown in FIG. 1 .

FIG. 3 is a pictorial view of an embodiment of the point-of-sale pole display and interface formed in accordance with the present invention.

FIG. 4 is a block diagram of the point-of-sale pole display and interface shown in FIG. 3 .

FIG. 5 is a schematic diagram of an embodiment of the point-of-sale pole display shown in FIG. 4 .

Program code listings that direct the operation of a microcontroller in the point-of-sale pole display assembly shown in FIG. 5 are incorporated in this document as an appendix.

In accordance with the present invention, a pole display assembly 26 is provided, the external appearance of which is disclosed in U.S. Pat. No. D462,983, issued Sep. 17, 2002, which is incorporated herein by reference, is shown in FIG. 3 and preferably incorporates a port powered Universal Serial Bus (USB) interface in accordance with the present invention. Although the most common physical configuration of a customer pole display includes a display unit mounted on a pole, this invention is equally applicable to other physical configurations without the use of a pole. Other common display configurations include table, wall, and ceiling mounted displays, such as display Model Nos. LT9000 and TD3000, which are commercially available from Logic Controls, Inc., New Hyde Park, N.Y. 10040.

Reference to USB specifications herein is intended to refer to all existing, as well as future, Universal Serial Bus (USB) specifications including without limitation the current USB 2.0 specification. The interface between the pole display assembly 26 and a point-of-sale (POS) computer terminal is preferably provided through a USB interface cable and connector 28 without the need for a separate power adapter, which is required in the conventional system shown in FIG. 1 .

A block diagram of an embodiment of the customer pole display assembly with port powered USB interface is shown in FIG. 4 and is substantially less complex than that shown in the conventional approach of FIG. 2 . The assembly of FIG. 4 essentially eliminates the power adaptor and AC rectifier and voltage regulator functional blocks shown in FIG. 2 .

A USB interface circuit 30 is preferably coupled to a USB bus through an optional connector 31 , which is connected between the POS computer terminal (not shown) and pole display assembly 26 , and establishes USB compatibility for data passing between these components. The microcomputer circuit 32 preferably provides the appropriate data and commands to a display 34 in response to information received from the POS computer terminal. The USB bus preferably provides the 5VDC power required by the USB interface 30 , microcontroller circuit 32 , and a DC-DC converter circuit 34 .

The DC-DC converter 36 preferably provides 4.7VAC and 40VDC required by the display 34 from the 5VDC or 12VDC obtained from the USB bus. A serial interface circuit 38 and a parallel interface circuit 40 are also optionally provided in the pole display assembly 26 to enable interfacing with a parallel port, such as a printer, and/or a serial port, such as an RS232 port. The display 34 is optionally connected to the microcontroller circuit 32 and converter circuit 36 through a connector 33 and the USB interface is optionally connected to the USB bus through a connector 31 to enable a portion of the assembly 26 to be provided as an in-line USB interface adapter.

However, in accordance with USB specifications, power available from the USB bus is limited to a maximum of 500 ma. Accordingly, the overall pole display assembly preferably operates efficiently such that the total current requirement is less than 500 ma. Thus, the DC-DC converter 34 is preferably implemented as a high-efficiency circuit, and the microcontroller 32 is preferably selected as a low-power consumption device. Reference to USB specifications herein is intended to refer to all existing as well as future Universal Serial Bus (USB) specifications including without limitation the current USB 2.0 specification.

FIG. 5 shows a schematic diagram of a preferred embodiment of the customer pole display assembly 26 shown in FIG. 4 , which is provided for purposes of example only and is not in any way intended to limit the scope of the present invention. The pole display assembly 26 preferably includes the USB interface circuit 30 , microcontroller circuit 32 , display circuit 34 , DC-DC controverter circuit 36 , and power supply circuit 42 . The optional serial interface circuit 38 and parallel interface circuit 40 may also be included in the assembly 26 as discussed above.

The microcontroller U 6 is preferably implemented by an 8052 microcontroller U 6 , which is commercially available from Intel Corporation (www.intel.com) with various additional peripheral devices, such as an X24C16 serial eeprom, which is commercially available from Xicor Corporation (www.xicor.com), a watchdog reset circuit including resistors R 4 , R 5 , R 6 , and R 17 , capacitors C 10 , C 11 , C 12 , C 13 , C 14 , diodes D 6 , D 7 , and and-gates U 9 B, U 9 C, and various jumpers JP 4 - 8 , which are preferably used to configure the display.

The microcontroller circuit 32 provides information to the display 34 , which is preferably implemented using a DN2029A vacuum fluorescent display with built-in drivers, which is commercially available from Noritake Corporation (www.noritake-itron.com). The USB interface circuit 30 is preferably implemented using a PD1USBD12 USB interface device U 1 , which is commercially available from Philips Semiconductor Corporation (www.semiconductors.philips.com) with various additional discrete components, such as the resistor, capacitor, and inductors shown in FIG. 5 .

The optional serial interface circuit 38 is preferably implemented using an RS232 transceiver U 5 in conjunction with additional discrete capacitors, resistors, diodes, transistors, and jumpers. The serial interface circuit 38 is controlled by the microcontroller circuit 32 and provides bidirectional transfer capability between the microcontroller circuit 32 and an external serial device in accordance with RS232 protocol. The optional parallel interface circuit 40 is also preferably controlled by the microcontroller circuit 32 and implemented using tri-state buffers U 3 , U 4 , invertors U 10 A-E, and flip-flops U 7 A, B. The parallel interface circuit 40 provides the capability of transferring parallel data to and from an external parallel device, such as a printer or computer.

As shown in FIG. 5 , the DC-DC converter 36 includes transistors Q 3 , Q 4 and transistor T 1 , which are its primary components. Transistors Q 3 and Q 4 preferably convert the 5VDC, 12VDC, or 24VDC input voltage obtained from the USB interface to an AC voltage signal, which is then provided to the transformer T 1 . Transformer T 1 is preferably adapted to simultaneously provide 4.7VAC and 40VDC, through operation of the network including diode D 8 , capacitor C 19 and resistor R 23 , to the display 34 .

Pin 4 of transformer T 1 is preferably connected to pin 1 of transformer T 1 through resistor R 41 and capacitor C 37 . Pin 4 of transformer T 1 is also connected to the 5VDC and 12VDC power sources, which may be obtained from the USB bus, through inductors L 5 and FB 4 , respectively. Pin 1 of transformer T 1 is preferably connected to the drain terminal (pin 2 ) of transistor Q 4 , and the source terminal of transistor Q 4 is connected to pin 4 of transformer T 1 through capacitor C 33 . The source terminal of transistor Q 4 is also connected to ground and the 12VDC supply through capacitor C 15 and inductor FB 4 .

Pin 3 of transformer T 1 is preferably connected to the 12VDC supply through resistor R 24 , capacitor C 20 , resistor R 22 , and inductor FB 4 . Pin 4 of transformer T 1 is preferably connected to the 12VDC supply through capacitor C 33 , resistor R 21 , capacitor C 17 , resistor R 22 , and inductor FB 4 . The collector of transistor Q 2 is connected to the 12VDC supply through resistor R 20 and inductor FB 4 . The base of transistor Q 2 is preferably connected to the 12VDC supply through resistor R 22 and inductor FB 4 . The collector of transistor of Q 2 is preferably connected to the gate terminal of transistor Q 4 and the 12VDC supply through capacitor C 17 , resistor R 22 , and inductor FB 4 .

Pin 3 of transformer T 1 is connected through diodes D 9 , D 10 , resistor R 22 , and inductor FB 4 to the 12VDC supply. Resistor R 25 and capacitor C 18 are preferably connected from a point between the back-to-back connected anodes of diodes D 9 and D 10 to ground. Pins 2 and 5 of transformer T 1 are connected to ground. Pin 7 of transformer T 1 is preferably connected to the anode of diode D 8 and the cathode of diode of D 8 is connected to ground through the parallel combination of capacitor C 19 and resistor R 23 .

Pin 9 of the microcontroller U 6 is preferably coupled to the base of transistor Q 3 . This enables the DC-DC converter to be selectively disabled by the microcontroller U 6 to conserve power and remain within the maximum power guidelines provided for in the USB specification.

One of the benefits of the USB is bus-powered devices, that is, devices which obtain power from the bus and require no external plug packs or additional cables. However, there are limitations to this feature.

A USB device specifies its power consumption, which is expressed in 2 mA units, in a configuration descriptor. A device cannot increase its power consumption, greater than what it specifies during enumeration, even if it looses external power. Enumeration is the process of deterring what device has just been connected to the bus and what parameters it requires, such as power consumption. There are three classes of USB functions; low-power bus powered functions, high-power bus powered functions, and self-powered functions.

Low-power bus powered functions draw all power from the USB bus and cannot draw any more than one unit load. The USB specification defines a unit load as 100 mA. Low-power bus powered functions must also be designed to work down to a voltage of 4.40V and up to a maximum voltage of 5.25V measured at an upstream plug of the device. High-power bus powered functions draw all power from the bus and cannot draw more than one unit load (100 mA max) until configuration or enumeration has been completed, after which it can then drain 5 unit loads (500 mA max) provided the device requests this power in its descriptor. Thus, since the typical bus powered device cannot draw more than 100 mA before enumeration, the microcontroller U 6 preferably disables the DC-DC converter 36 by turning transistor Q 3 on. Following enumeration, the microcontroller U 6 turns transistor Q 3 off, which enables the pole display assembly to draw up to a maximum of 500 mA.

Additional information concerning the design of DC-DC converter circuits is provided in G. Ledwich, DC - DC Converter Basics , pp. 1-12 (1998), and Application Note 2031, DC - DC Converter Tutorial , Dallas Semiconductor Corporation, pp. 1-8 (2000), which are incorporated herein by reference.

The pole display assembly 26 is preferably adapted to operate with different configurations for flexibility during production. Thus, the assembly 26 is capable of operating with the USB interface circuit 30 , the serial interface circuit 38 , and/or the parallel interface circuit 40 . Since the serial and parallel interface circuits 38 , 40 require an external power source, the power supply 42 incorporates a bridge rectifier circuit, which includes diodes D 1 -D 4 , and a voltage regulator VR 1 to provide the power requirements for these configurations.

If the USB interface is to be used exclusively, the bridge and voltage regulator VR 1 are not required and need not be installed. In this case, the DC input power is preferably obtained directly from the USB port connector as discussed above. Since the USB specification requires that power consumption cannot be more than 500 mA, the power supplied to the display 34 is preferably controlled by the microcontroller U 6 . This is preferably achieved by controlling the operation of the DC-DC converter 36 using a control signal from the microcontroller U 6 that is connected to the base of transistor Q 3 as discussed above.

It is to be understood that the pole display assembly 26 shown in FIG. 6 could as well be implemented using different devices, such as without limitation one or more microprocessors, application specific integrated circuits (ASIC), programmable logic devices, programmable logic arrays, discrete components, integrated circuits, and the like while remaining within the scope of the present invention.

An assembly code listing of the programs that direct operation of the microcontroller in the display assembly 26 in accordance with the present invention are incorporated in this document and provided as appendix. This material is subject to copyright ownership by Logic Controls, Inc. The file <Ascfont.dat> includes all character font data; the file <D12cmd.h> includes all USB IC command codes; the file <DN2029A.ASM> includes glass scanning subroutines; the file <INIT_INT.ASM> includes all initialization subroutines and interrupt subroutines; the file <IO.ASM> includes all input/output subroutines; the file <LD9UsbTb.dat> includes USB Descriptors and Strings table; the file <Ldcmd.h> includes constant definitions; and the file <LDO.asm> includes main loop subroutine and others.

Thus, the advantages provided by the customer pole display with port-powered USB interface formed in accordance with the present invention include the following:

1. eliminating the need for an external power adaptor;

2. eliminating the need for an AC-DC power converter internal to the pole display;

3. reducing system power consumption;

4. reducing the number of internal components, which drastically improves cooling and reliability, and simplifies manufacture and assembly;

5. reducing product cost; and

6. replacing the outdated RS232 interface by the newer, widely accepted USB interface, which has many inherent advantages, such as plug-and-play capability.

Although illustrative embodiments of the present invention have been described herein with reference to the accompanying drawing, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the invention.