Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 DESCRIPTION PT6955 is an LED Controller driven on a 1/4 to 1/7 duty factor. Twelve/nine segment output lines, 4 to 7 grid output lines, one display memory, control circuit are all incorporated into a single chip to build a highly reliable peripheral device for a single chip microcomputer. Serial data is fed to PT6955 via a three-line serial interface. Housed in a 24-pin SOP, PT6955’s pin assignments and application circuit are optimized for easy PCB Layout and cost saving advantages. FEATURES • • • • • CMOS Technology Low Power Consumption 8-Step Dimming Circuitry Serial Interface for Clock, Data Input, Strobe Pins Available in 24-pin, SOP APPLICATION • Micro-computer Peripheral Device PT6955 V1.5 -1- June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 BLOCK DIAGRAM PT6955 V1.5 -2- June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 INPUT/OUTPUT PORT CONFIGURATION The schematic diagrams of the input and output circuit of the logic section are shown below. Input Pins: CLK, STB & DIN Output Pins: SG10/GR7, SG11/GR6, SG12/GR5 VDD GND GND Output Pins: GR1 to GR4 Output Pins: SG1 to SG9 VDD VDD GND GND PT6955 V1.5 -3- June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 PIN CONFIGURATION PIN DESCRIPTION Pin Name I/O OSC I DIN I CLK I STB I VDD - SG1 ~ SG9 O SG10/GR7 ~ SG12/GR5 O GND GR4 ~ GR1 O PT6955 V1.5 Description Pin No. Oscillator Input Pin A resistor is connected to this pin to determine 1 the oscillation frequency Data Input Pin This pin inputs serial data at the rising edge of the 2 shift clock (starting from the lower bit) Clock Input Pin 3 This pin reads serial data at the rising edge. Serial Interface Strobe Pin The data input after the STB has fallen is processed 4 as a command. When this pin is "HIGH", CLK is ignored. Power Supply 5, 18 Segment Output Pins 6 ~ 14 (p-channel, open drain) Segment Output Pin/Grid Output Pin 15 ~ 17 (CMOS Output) Ground Pin 19, 24 Grid Output Pins (n-channel, open drain) 20 ~ 23 -4- June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 FUNCTION DESCRIPTION COMMANDS A command is the first byte (b0 to b7) inputted to PT6955 via the DIN Pin after STB Pin has changed from “HIGH” to “LOW” State. If for some reason the STB Pin is set to “HIGH” while data or commands are being transmitted, the serial communication is initialized, and the data/commands being transmitted are considered invalid. COMMAND 1: DISPLAY MODE SETTING COMMANDS PT6955 provides 4 display mode settings as shown in the diagram below: As stated earlier a command is the first one byte (b0 to b7) transmitted to PT6955 via the DIN Pin when STB is “LOW”. However, for these commands, Bit No. 3 to Bit No.6 (b2 to b5) are ignored, Bit No.7 & Bit No.8 (b6 to b7) are given a value of “0”. The Display Mode Setting Commands determine the number of segments and grids to be used (1/4 to 1/7 duty, 12 to 9 segments). When these commands are executed, the display is forcibly turned off. A display command “ON” must be executed in order to resume display. If the same mode setting is selected, no command execution is take place, therefore, nothing happens. When Power is turned “ON”, the 7-Grid, 9-Segment Mode is selected. MSB 0 0 - - - Not Relevant PT6955 V1.5 - LSB b1 b0 Display Mode Settings: 00: 4 digits, 12 segments 01: 5 digits, 11 segments 10: 6 digits, 10 segments 11: 7 digits, 9 segments -5- June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 COMMAND 2: DATA SETTING COMMANDS The Data Setting Commands executes the Data Write Mode for PT6955. The Data Setting Command, the bits 5 and 6 (b4, b5) are ignored, bit 7 (b6) is given the value of “1” while bit 8 (b7) is given the value of “0”. Please refer to the diagram below. When power is turned ON, bit 4 to bit 1 (b3 to b0) are given the value of “0”. MSB 0 1 - - Not Relevant LSB b3 b2 b1 b0 Data Write Mode Settings: 00: Write Data to Display Mode Address Increment Mode Settings (Display Mode) 0: Increment Address after Data has been Written 1: Fixed Address Mode Settings: 0: Normal Operation Mode 1: Test Mode PT6955 V1.5 -6- June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 COMMAND 3: ADDRESS SETTING COMMANDS Address Setting Commands are used to set the address of the display memory. The address is considered valid if it has a value of “00H” to 0DH”. If the address is set to 0EH or higher, the data is ignored until a valid address is set. When power is turned ON, the address is set at “00H”. Please refer to the diagram below. MSB 1 1 - LSB b3 b2 b1 b0 - Not Relevant Address: 00H to 0DH Display Mode and RAM Address Data transmitted from an external device to PT6955 via the serial interface are stored in the Display RAM and are assigned addresses. The RAM Addresses of PT6955 are given below in 8 bits unit. SG1 SG4 SG5 SG8 SG12 00HL 00HU 01HL DIG1 02HL 02HU 03HL DIG2 04HL 04HU 05HL DIG3 06HL 06HU 07HL DIG4 08HL 08HU 09HL DIG5 0AHL 0AHU 0BHL DIG6 0CHL 0CHU 0DHL DIG7 b0 PT6955 V1.5 SG9 b3 b4 b7 xxHL xxHU Lower 4 bits Higher 4 bits -7- June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 COMMAND 4: DISPLAY CONTROL COMMANDS The Display Control Commands are used to turn ON or OFF a display. It also used to set the pulse width. Please refer to the diagram below. When the power is turned ON, a 1/16 pulse width is selected and the displayed is turned OFF. MSB 1 0 - - Not Relevant LSB b3 b2 b1 b0 Dimming Quantity Settings: 000: Pulse width = 1/16 001: Pulse width = 2/16 010: Pulse width = 4/16 011: Pulse width = 10/16 100: Pulse width – 11/16 101: Pulse width = 12/16 110: Pulse width = 13/16 111: Pulse width = 14/16 Display Settings: 0: Display Off 1: Display On PT6955 V1.5 -8- June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 DISPLAY TIMING WAVEFORM SERIAL COMMUNICATION FORMAT The following diagram shows the PT6955 serial communication format. PT6955 V1.5 -9- June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 SWITCHING CHARACTERISTICS WAVEFORM where: PWCLK (Clock Pulse Width) ≥ 400ns tsetup (Data Setup Time) ≥100ns tCLK-STB (Clock - Strobe Time) ≥ 1µs tTZH (Rise Time) ≤ 1 µs tTZL ≤ 1µs PT6955 V1.5 PWSTB (Strobe Pulse Width) ≥ 1µs thold (Data Hold Time) ≥ 100ns tTHZ (Fall Time) ≤ 10µs fosc = Oscillation Frequency tTLZ ≤ 10 µs - 10 - June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 APPLICATIONS Display memory is updates by incrementing addresses. Please refer to the following diagram. The following diagram shows the waveforms when updating specific addresses. PT6955 V1.5 - 11 - June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 RECOMMENDED SOFTWARE FOLWCHART START Delay 200 ms SET COMMAND 2 (WriteData) SET COMMAND 3 Clear Display RAM (See Note 5) INITIAL SETTING SET COMMAND 1 SET COMMAND 4 (88H ~ 8FH : Display ON) MAIN PROGRAM SET COMMAND 2 (READ KEY & WRITE DATA INCLUDED) MAIN LOOP SET COMMAND 3 SET COMMAND 1 SET COMMAND 4 END Notes: 1. Command 1: Display Mode Commands 2. Command 2: Data Setting Commands 3. Command 3: Address Setting Commands 4. Command 4: Display Control Commands 5. When IC power is applied for the first time, the contents of the Display RAM are not defined; thus, it is strongly suggested that the contents of the Display RAM must be cleared during the initial setting. PT6955 V1.5 - 12 - June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 SOP 24L (300MIL) THERMAL PERFORMANCE IN STILL AIR JUNCTION TEMPERATURE: 100℃ PT6955 V1.5 - 13 - June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 ABSOLUTE MAXIMUM RATINGS (Unless otherwise stated, Ta=25℃, GND=0V) Parameter Supply Voltage Logic Input Voltage Driver Output Current/Pin Maximum Driver Output Current/Total Operating Temperature Storage Temperature Symbol VDD VI IOLGR IOHSG ITOTAL Topr Tstg Rating -0.5 to +7.0 -0.5 to VDD+0.5 +250 -50 400 -40 ~ +85 -65 ~ +150 Units V V mA mA mA ℃ ℃ RECOMMANDED OPERATING RANGE (Unless otherwise stated, Topr=-40 to +85℃, GND=0V) Parameter Symbol Min. Typ. Max. Logic Supply Voltage VDD 4.5 5 5.5 Dynamic Current (see note) IDDdyn 5 High-Level Input Voltage VIH 0.8VDD VDD Low-Level Input Voltage VIL 0 0.3VDD Note: Test Condition: Set Display Control Commands = 80H (Display Turn Off State) PT6955 V1.5 - 14 - Unit V mA V V June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 ELECTRICAL CHARACTERISTICS (Unless otherwise stated, VDD=5V, GND=0V, Ta=25℃) Parameter Symbol Test Condition VO=VDD-1V IOHSG(1) SG1 to SG9, SG10/GR7 to SG12/GR5 High-Level Output Current VO=VDD-2V IOHSG(2) SG1 to SG9, SG10/GR7 to SG12/GR5 VO=0.3V Low-Level Output Current IOLGR GR1 to GR4, SG10/GR7 to SG12/GR5 VO=VDD-1V Segment High-Level ITOLSG SG1 to SG9, Output Current Tolerance SG10/GR7 to SG12/GR5 High-Level Input Voltage VIH Low-Level Input Voltage VIL Oscillation Frequency fosc R=51KΩ PT6955 V1.5 - 15 - Min. Typ. Max. Unit -10 -14 -30 mA -20 -25 -50 mA 100 140 - mA - - ±5 % 0.8VDD 350 500 0.3VDD 650 V V KHz June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 APPLICATION CIRCUIT Notes: 1. The capacitor (0.1µF) connected between the GND and VDD Pins must be located as near as possible to the PT6955 chip. 2. The PT6955 power supply is separate from the application system power supply. COMMON CATHODE TYPE LED PANEL SE G1 SE G2 SE G3 SE G4 SE G5 SE G6 SE G7 SE G8 PT6955 V1.5 a COM/DIG ITAL (GRID) b a c d b f g e c e f g d oh h - 16 - June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 ORDER INFORMATION Valid Part Number PT6955 PT6955 V1.5 Package Type 24pins, SOP, 300mil - 17 - Top Code PT6955 June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 PACKAGE INFORMATION 24 PINS, SOP, 300 MIL Symbols A A1 B C D E e H h L α PT6955 V1.5 Min. 2.35 0.10 0.33 0.23 15.20 7.40 Nom. Max. 2.65 0.30 0.51 0.32 15.60 7.60 1.27 bsc. 10.00 0.25 0.40 0° - 18 - 10.65 0.75 1.27 8° June, 2005 Tel: 886-2-66296288 Fax: 886-2-29174598 URL: http://www.princeton.com.tw LED Driver IC PT6955 Notes: 1. Dimensioning and tolerancing per ANSI Y 14.5-1982. 2. Dimension “D” does not include mold flash, protrusions or gate burrs. Mold Flash, protrusion or gate burrs shall not exceed 0.15mm (0.006 in)per side. 3. Dimension “E” does not include interlead flash protrusions. Interlead flash or protrusions shall not exceed 0.25 mm (0.010 in) per side. 4. The chamfer on the body is optional. It is not present, a visual index feature must be located within the crosshatched area. 5. “L” is the length of the terminal for soldering to a substrate. 6. “N” is the number of terminal position. (N=24) 7. The lead width “B” as measured 0.36 mm (0.014 in) or greater above the seating plane, shall not exceed a maximum value of 0.61mm (0.24 in). 8. Controlling dimension: MILLIMETER. 9. Refer to JEDEC MS-013, Variation AD. JEDEC is the trademark of JEDEC SOLID STATE TECHNOLOGY ASSOCIATION. PT6955 V1.5 - 19 - June, 2005