IXYS MX881 Xenon Flash Controller & LED Torch Driver Features: General Description * Highly Integrated Solution that includes: Optimized Flyback Boost Converter Controller, IGBT Driver, 100mA LED Torch Driver, and Transformer Drive Transistor * Small Size (3mm x 5mm DFN-16) * High Efficiency * 3.0 to 5.5 Volt Battery Operation * 1.65 to 5.5 Volt Digital Interface Operation * Low Shut Down Current: 0.1A * SPI and I2C Bus Compatibility * Programmable Average Battery Current: (50mA - 220mA) * Programmable Output Voltage: (300V - 330V) The MX881 offers a highly integrated Xenon Flash controller, providing an ideal solution for small form factor flash and torch lighting applications. The MX881 integrates a user programmable Controller, IGBT Driver, 100mA LED Torch Driver, and Transformer Drive Transistor to significantly reduce component count, solution size, and design complexity. The Boost Control Logic manages the peak primary current and off time to optimize charge time and control average battery current. Applications: * Camera Cell Phones, Digital Still Cameras, and Optical Film Cameras Ordering Information Part No. MX881R MX881RTR Qty 73 2000 Description 3mm X 5mm DFN-16 DFN-16 Tape & Reel The Charge Cycle Control starts the charge cycle on a low to high transition of the CHARGE input. Then detects when the output voltage has reached the desired voltage and stops the Boost Control Logic, while asserting the DONE output signal. The SPI/I2C serial interface adds the flexibility of 6 programmable average battery currents and 4 programmable high voltage output levels for the flash function. Typical Application VHV VCC T1 1:10 min. MX881 CONTROLLER / DRIVER SW + 500V Total Switching Diodes L SEC VCC TRIGGER CAPACITOR Boost Control Logic DVCC 22 uF FLASH TUBE I PEAK DVCC VFB CHARGE DONE Charge Cycle Logic VOUT V BATT IGBTGATE FLASH IGBT DRIVER SPI / I2C X4 SPI / I2C Interface to set V OUT & I AVE IXYS IGBT I SET LED LED_EN Bandgap REF GND MX881 Drawing No. 088109 1 7/30/07 www.claremicronix.com IXYS MX881 Boost Switch: When turned on, current flows in the primary of the flyback transformer. The energy stored in the transformer is transferred to the secondary as high voltage when the boost switch is turned off. IGBT Driver: Switches the VCC supply to the IGBT gate when the FLASH signal is brought high. If FLASH is low, the IGBT gate is driven to ground. LED Driver: When LED_EN is high, the LED pin will sink 100mA to GND. If LED_EN is low, the LED pin is high impedance. Pin Description Pin No. 11 7 Pin Name VCC DVCC 15 CHARGE 6 DONE 12 VFB 14 FLASH 16 ISEL 1 SCEn 4 SCLK 2 SDATA 3 SW 13 LSEC 9 IGBTGATE 5 LED_EN 10 LED Exposed Pad 8 MX881 Drawing No. 088109 Description Supply voltage from battery, (3.0V - 5.5V). Must be connected to VDVCC. Digital supply voltage for I/O logic (1.65V-5.5V) Low level stops the charging cycle and puts the device into power down mode. Charge remains on the high voltage capacitor. A high level starts a charging cycle. Charging continues until either the correct voltage is reached or CHARGE is brought low. Open drain output that transitions high when the capacitor reaches the desired voltage. This output is normally high except when charging so that standby current is minimized. (Pull-up resistor not sourcing current). Feedback voltage input from voltage divider that determines when the output has reached the desired voltage. A high level will cause the IGBT to turn on firing the flash. A low level will turn the IGBT off. FLASH can be brought low to shorten the flash pulse for red-eye reduction. 2 High level enables the I C interface, low level enables SPI interface. Serial port chip enable. A low on this pin enables the SPI interface to receive data. If SCEn is asserted low while in the I2C mode, the serial interface and control register are reset. Clock input for SPI and I2C interface. Data input and output for SPI interface. Data input and acknowledge/data output for 2 2 I C interface. This output is open drain for I C output data. Connection to internal power transistor that drives the negative terminal of the transformer primary coil. Connection to negative terminal of the transformer secondary. This input is grounded internally through a low impedance used to sense the secondary transformer current. IGBT Gate driver output. A high level will cause the 100mA LED current regulator to turn on. VF = VBATT 100mA LED current regulator. Connect the cathode of the torch LED to this pin. VF = VBATT GND Ground Terminal. N/C No Connect. Do not connect to any signal, ground or power source. 2 7/30/07 www.claremicronix.com IXYS MX881 Absolute Maximum Ratings Symbol VCC, DVCC VIN VSW TSTG Parameter DC Supply Voltage DC Input Voltage Voltage On SW pad Storage Temperature Rating 0.3 to 7.0 -0.3 to VCC+0.3 -0.3 to 55 -40 to +150 Unit V V V o C Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximumrated conditions for extended periods may affect device reliability. Recommended Operating Conditions Symbol VCC DVCC VIN VSW TJ Parameter Analog and Digital Supply Voltage Digital I/O Supply Voltage DC Input Voltage Voltage On SW pad Junction Temperature MX881 Drawing No. 088109 Rating 3 to 5.5 1.65 to 5.5 0 to DVCC 0 to 40 -20 to +115 3 Unit V V V V o C 7/30/07 www.claremicronix.com IXYS MX881 DC Characteristics Junction temperature range -20 to +115C Symbol Parameter Condition Supply Voltage - Analog and AVCC voltage doubler DVCC Supply Voltage - Digital I/O ICC Supply Current (When Charging) @ 25 C ISTANDBY Supply Current (Not Charging) @ 25 C Vsw = 40V ISW_LEAK SW pin Leakage Current Schmitt trigger, positive-going 1.65V < DVCC < 2.4V VT+ threshold (All digital inputs) Schmitt trigger, negative-going 1.65V < DVCC < 2.4V VTthreshold (All digital inputs) 1.65V < DVCC < 2.4V Vhys Hysteresis, Schmitt trigger Schmitt trigger, positive-going 2.4V < DVCC < 3.6V VT+ threshold (All digital inputs) Schmitt trigger, negative-going 2.4V < DVCC < 3.6V VTthreshold (All digital inputs) 2.4V < DVCC < 3.6V Vhys Hysteresis, Schmitt trigger Schmitt trigger, positive-going 3.6 < DVCC <5.5V VT+ threshold (All digital inputs) Schmitt trigger, negative-going 3.6V < DVCC <5.5V VTthreshold (All digital inputs) 3.6V < DVCC <5.5V Vhys Hysteresis, Schmitt trigger VIN = DVCC or GND IIN Input Current 2K to DVCC VOL Output Low Voltage 2K to Ground VOH Output High Voltage DVCC = 3.0V RSW SW Switch on resistance DVCC=3.0V, @ 25C RSW SW Switch on resistance VLED > 0.5V ILED LED drive current IPEAK Primary Peak Current VTRIP Output Voltage Trip Point OVS = 11 OVS = 10 OVS = 01 OVS = 00 MX881 Drawing No. 088109 4 Min Typ Max Unit 3 3.6 5.5 V 1.65 3.3 5.5 4 V mA A nA 1.3 V 0.1 30 V V 0.4 0.15 1.6 0.65 0.16 V V 0.9 0.17 -10 DVCC-0.3 .15 .19 85 1.20 1.16 1.12 1.10 V .25 .25 100 .7 1.23 1.19 1.15 1.12 2.1 V 10 0.15 V V A V V .50 .32 115 1.26 1.22 1.18 1.14 mA A V V V V 7/30/07 www.claremicronix.com IXYS MX881 AC Characteristics Junction temperature range 0 to + 115C Symbol TSTART TEND Parameter CHARGE High to Beginning of Charge Cycle CHARGE Low to End of Charge Cycle TIGBT-ON FLASH High to IGBTGATE High TIGBT-OFF FLASH Low to IGBTGATE Low TLED-ON TLED-OFF LED_EN High to Iout > 90mA LED_EN Low to Iout < 1mA Condition Min Typ Max Unit 110 S 100 nS 100 nS 100 nS TBD TBD S S CL = 6.8nF, 10% to 90% CL = 6.8nF, 90% to 10% Control Register The MX881 control register is a 5 bit register that allows the user to program the maximum output voltage and the maximum average battery current during the charge cycle. Table1 shows how the bits in the control register are assigned. ABC(2:0) are used to set the average battery current and OVS(1:0) are used to set the output voltage selection reference. Table 1 - Control Register BIT: Control: D4 OVS1 D3 OVS0 D2 ABC2 D1 ABC1 D0 ABC0 Output Voltage Selection The MX881 limits the high voltage placed on the external capacitor by comparing a divided down version of the secondary flyback voltage to an internal voltage. This internal voltage is programmable to 4 discrete values to allow the user to change the flash energy. The external voltage divider ratio needed to obtain 330V maximum output voltage should be 269 to 1. This external resistor divider network is also used to form a low pass filter with an internal capacitor so it is important that the equivalent resistance of the voltage divider network be 3K ohms. Table 2 shows the internal reference values used for possible values of the capacitor charge voltage. The default value is 11. Table 2 - Output Voltage Selection OVS Value (Binary) 11 10 01 00 MX881 Drawing No. 088109 Reference Voltage (VTRIP) 1.23 1.19 1.15 1.12 5 Capacitor Voltage 330 320 310 300 7/30/07 www.claremicronix.com IXYS MX881 Average Battery Current The 3 bits (ABC2 - ABC0) of the control register are used to program the maximum average battery current during a charge cycle. The MX881 does this by limiting the minimum off time during a switching cycle. The off time compensates for variation of the battery voltage so that the average current is independent of battery voltage. The default value of ABC is 101. With the default value of ABC, the average battery current control circuits are disabled for maximum efficiency, and the maximum battery current is approximately 220mA. The average current versus the output voltage is shown in Figure1. The battery current peak value is preset internally to 0.7A. This current must be averaged by placing an external bypass capacitor from VCC to ground. A 10uF capacitor is recommended for good current smoothing and averaging. Figure 1 - Average Battery Current Average Battery Current Setting of 50mA (ABC = 000) 60 50 mA 40 VCC = 3.0V 30 VCC = 5.5V 20 10 0 0 100 200 300 400 V MX881 Drawing No. 088109 6 7/30/07 www.claremicronix.com IXYS MX881 mA Average Battery Current Setting of 100mA (ABC = 001) 140 120 100 80 60 40 20 0 VCC = 3.0V VCC = 5.5V 0 100 200 300 400 V Average Battery Current Setting of 150mA (ABC = 010) 200 mA 150 VCC = 3.0V 100 VCC = 5.5V 50 0 0 100 200 300 400 V MX881 Drawing No. 088109 7 7/30/07 www.claremicronix.com IXYS MX881 Serial Interface The MX881 has a 4 wire serial interface that is capable of operating in two modes: I2C or SPI. Both modes transfer 8 bits of information but only 5 bits are actually used to set the internal control register. Table 3 - Interface Modes ISEL 1 0 Active Interface Standard I2C slave only serial interface Standard 3-wire SPI I2C Bus Interface The I2C interface (follows the standard bus protocol and timing as defined by Philips). For complete information on this bus, refer to www.semiconductors.philips.com The MX881 acts as a slave device on the I2C bus and is compatible with both the HS (High Speed) Mode and Fast Mode formats. Its primary function is as a receiver, receiving data from a master device that is used to set a single 5 bit register that determines the average battery current and the output voltage. It will act as a transmitter after receiving a read command. During a read, the register data will be output onto the I2C bus. When receiving a non-broadcast message, the MX881 will respond with an acknowledge bit, in which it pulls the data bus low at the appropriate time. Data packets begin with the Master issuing a START command (S) and end with the Master issuing a STOP command (P). A Restart command is simply another START command that is issued before a STOP command. Note that with START and STOP commands that SDATA transitions while SCLK is high. Conversely, for all other bits, SDATA is only allowed to transition while SCLK is low. Figure 2 - I2C Sequences SDA TA T I2 C -C S TI2 C -S C T I2 C -D S TI2 C -C P T I2 C -D H TI2 C -P C SCLK DA TA is s table during high per iod of SCLK 1 1 1 1 1 1 Slave Address 0 0 ACK 0 START S R/Wn Write Sequence Overview Shaded boxes represent bits sourced by the MX889. 0 D 7 D 6 D 5 D 4 D 3 D 2 D 1 D 0 Data Byte - Written to control Register 0 P STOP Unshaded boxes represent bits sourced by the master . 0 STOP ACK STA RT 1 1 1 1 1 Slave Address Slave address is 0111111b. MX881 Drawing No. 088109 8 1 0 1 1 0 1 1 1 1 0 Data Byte - Register contents placed on bus by MX889 0 P STOP 1 ACK 0 ACK S START Status Read Sequence R/Wn The slave address is internally fixed to 0111111 b. 7/30/07 www.claremicronix.com IXYS MX881 To write to the MX881 register, the master device will first issue a Start Bit. It will then transmit a 7-bit address. In the MX881, the address is internally set to 0111111b. If the address in the message corresponds to the address of the MX881, the device will issue an acknowledge. The master will send 8 bits of data. These 8 bits will be written into the control register. Another Acknowledge will follow. The write sequence is illustrated in Figure 2. To read the control register the master issues a read command by setting the R/Wn bit. The master will then tri-state the data bus while the MX881 outputs data. See the example in Figure 2. 3-Wire SPI (Serial Peripheral Interface) A standard 3-wire bi-directional serial interface is available (Figure 3). The interface signals are the serial clock: SCLK, the serial data line: SDATA, and the serial chip enable: SCEn. SDATA is bidirectional. In write mode, the microcontroller is writing to the MX881 control register. Each packet sent contains an 8-bit command followed by 8 bits of data to be written into the register. When SCEn goes low, the rising edge of SCLK clocks in 8 bits, MSB first. At the end of the first transmission byte, the MX881 determines whether the first byte is a recognized command. The MX881 only recognizes one write command "00011110". If the command is recognized, the next byte clocked into the MX881 will be written into the control register. This sequence is illustrated in Figure 3. In read mode, a command is received which tells the MX881 to output the control register contents. The MX881 only recognizes one read command: "01011110". If the correct command is recognized, the MX881 will output 8 bits of data beginning on the first falling edge of SCLK after the rising edge of SCLK in which the last transmission bit was clocked in. In this manner, the first control register bit will be available to the microcontroller on the next rising edge of SCLK. SCEn must remain low while the MX881 is outputting data, going high after the MX881 has output the last bit. While the device is outputting data, the microcontroller must stop driving the SDATA line so that the MX881 can drive the data onto this bus. This sequence is also illustrated in Figure 3. Table 4 - Serial Interface Timing Symbol TCYCS THI, TLO TDS TDH TSS TSH TACCS TOHS TI2C_CS TI2C_SC TI2C_DS TI2C_DH TI2C_CP TI2C_PC MX881 Drawing No. 088109 Parameter Cycle Time Pulse Width Data Setup Time Data Hold Time SCEn Setup Time, Write SCEn Hold Time, Write Read Access Time Read Output Disable Time I2C Clock High to Start Bit I2C Start Bit to Clock Low I2C Data Valid to Clock High I2C Clock Low to Data Change I2C Clock High to Stop Bit I2C Stop Bit to Clock Low 9 Condition Min 250 50 50 30 30 30 CL = 100pF CL = 100pF Max 30 30 50 50 50 30 50 50 Units nS nS nS nS nS nS nS nS nS nS nS nS nS nS 7/30/07 www.claremicronix.com IXYS MX881 Figure 3 - 3-WIRE SPI SCEn SCLK SDATATo MX881 0 0 0 1 1 1 1 D7 0 D6 D5 D4 D3 D2 D1 D0 WriteCy cle SCEn TR TSS TF THI TSH TDH TCYCS SCLK TDS SDATA D7 TLO D6 D5 D4 D3 D2 D1 D0 WriteCy cleTiming SCEn SCLK SDATATo MX881 SDATA From MX881 Control Register 0 1 0 1 1 1 1 0 D4 D3 D2 D1 D0 ReadCy cle SCEn SCLK TOHS TACCS SDATA D7 D0 ReadCy cleTiming-Detailed . MX881 Drawing No. 088109 10 7/30/07 www.claremicronix.com IXYS MX881 Layout Notes T1 LDT565620ST-201 7 VPRI VCC 6 C1 1.0uF C2 10uF D1 BAV23S 4 1 VSEC 2 VHV 8 1 R1 133K, 1% 5 C3 22uF/350V R2 137K, 1% U1 SCEn 1 SDATA 2 3 SCLK 4 LED_EN 5 DONE 6 DVCC 7 C4 .1uF 8 SCEn SDATA SW ISEL CHARGE FLASH SCLK LSEC LED_EN VFB DONE VCC DVCC LED PROG IGBTGATE 16 ISEL 15 CHARGE 14 FLASH 13 12 VFB 11 R3 1K, 1% VCC LED 10 IGBTGATE 9 MX881 16 PIN DFN C4 .1uF VCC C1 R1 R2 R3 C2 MX881 Drawing No. 088109 11 7/30/07 www.claremicronix.com IXYS MX881 Layout Notes: * * * * * * * * * Parasitic capacitance on node VSEC or VPRI will cause loss of efficiency. Keep wires on this node as short as possible. Parasitic inductance on the transformer connections can cause overshoot during switching that could damage the part. Keep connections from the capacitors and MX881 to the transformer short. Also keep the connection from pin 2 of D1 to C3 as short as possible. The VFB node is sensitive to coupling from T1 and the VSEC node. The VSEC node ramps to over 300 volts in just a few nano-seconds. Keep R1, R2, and R3 as far from T1 as possible. If possible, shield resistors by placing on the other side of the board from T1. VCC should be well bypassed to average charge current to the battery and reduce noise to analog circuits within MX881. VFB is a very fast and short pulse. Keep VFB connection to R7 short to minimize capacitance on this node. If VFB has too much capacitance, the feedback voltage may be filtered so that the output voltage does not stop at 330V but continues to a much higher voltage. A good ground plane is extremely important. Large pulse currents of 0.7 amps will be flowing in the ground. The large bottom pad of the MX881 is the only ground pad and requires a low impedance return to C1, C2, and R7. The ground plane must have adequate clearance from high voltage nodes VHV and VSEC to avoid arcing. Also, the node connecting R1 to R2 will be at approximately 170V. R1 and R2 must be at least 1206 size surface mount to withstand 200V each. Transformer For 330V charger, the transformer should have a turns ratio of approximately 10 to insure that the flyback voltage on the primary side of the transformer does not damage the power switch internal to the MX881. The fly-back voltage should be equal to the output voltage divided by the turns ratio plus the VCC supply voltage. The fly-back voltage will be greater than this due to the energy stored in the transformer leakage inductance. The actual voltage will depend on the transformer leakage inductance and the parasitic capacitance of the circuits and layout. The MX881 is designed to work with a transformer having a primary inductance of approximately 10H. Larger values are acceptable as long as leakage inductance is small. Smaller primary inductance values may cause feedback pulses that are too short and lead to higher than expected output voltage. IXYS Corporation makes no representations or warranties with respect to the accuracy or completeness of the contents of this publication and reserves the right to make changes to specifications and product descriptions at any time without notice. Neither circuit patent licenses nor indemnity are expressed or implied. Except as set forth in IXYS' Standard Terms and Conditions of Sale, IXYS Corporation assumes no liability whatsoever, and disclaims any expressed or implied warranty, relating to its products including, but not limited to, the implied warranty of merchantability, fitness for a particular purpose, or infringement of any intellectual property right MX881 Drawing No. 088109 12 7/30/07 www.claremicronix.com IXYS World Wide Sales Offices IXYS Corporation 3540 Bassett Street Santa Clara, CA 925054 Tel: 408-982-0700 Fax: 408-496-0670 e-mail:sales@ixys.net United Kingdom IXYS Semiconductor Limited Langley Park Way Langley Park Chippenham Wiltshire SN 15 1GE - England Tel: 44 1249 444524 Fax: 44 1249 659448 sales@ixys.co.uk Micronix An IXYS Company 145 Columbia Aliso Viejo, CA 92656-1490 Tel: 1-949-831-4622 Fax: 1-949-831-4628 Sales Offices ASIA / PACIFIC Asian Headquarters IXYS Room 1016, Chia-Hsin, Bldg II, 10F, No. 96, Sec. 2 Chung Shan North Road Taipei, Taiwan R.O.C. Tel: 886-2-2523-6368 Fax: 886-2-2523-6368 bradley.green@ixys.co.uk Jhong@clare.com SALES OFFICES AMERICAS Eastern Region [Eastern North America, Mexico, South America] IXYS Corporation Beverly, MA Tel: 508-528-6883 Fax: 508-528-4562 wgh@ixys.net Check the IXYS Website for the local sales office nearest you. (www.ixys.com) Central Region [Central North America] IXYS Corporation Greensburg, PA Tel: 724-836-8530 Fax: 724-836-8540 neil.lejeune@westcode.com Western Region [Western North America] IXYS Corporation Solana Beach, CA Tel: 858-792-1101 slodor@ix.netcom.com http://www.claremicronix.com SALES OFFICES EUROPE European Headquarters IXYS Semiconductor GMBH Edisonstrasse 15 D- 68623 Lampertheim Germany Tel: 49-6206-503203 Fax: 49-6206-503286 marcom@ixys.de MX881 Drawing No. 088109 IXYS cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in this IXYS product. No circuit patent licenses nor indemnity are expressed or implied. IXYS reserves the right to change the specification and circuitry, without notice at any time. The products described in this document are not intended for use in medical implantation or other direct life support applications where malfunction may result in direct physical harm, injury or death to a person. Specification: MX881 (c)Copyright 2007, IXYS Corporation All rights reserved. Printed in USA. 13 7/30/07 www.claremicronix.com