MIC2870 Eval Board
Contents
1. Percentage of Maximum Register Value Current Per Channel mA Combined Current mA Current 96 03 00 of 02h Rtrset 0Q Rrnser 0Q 100 0000 187 5 375 0 90 0001 168 8 337 5 80 0010 150 0 300 0 70 0011 131 3 262 5 63 0100 118 1 236 3 56 0101 105 0 210 0 50 0110 93 8 187 5 44 7 0111 83 8 167 6 39 8 1000 74 6 149 3 35 5 1001 66 6 133 1 31 6 1010 59 3 118 5 28 2 1011 52 9 105 8 25 1 1100 47 1 94 1 22 4 1101 42 0 84 0 20 1110 37 5 75 0 18 1111 33 8 67 5 September 24 2013 Revision 1 2 Micrel Inc Evaluation Kit Overview The MIC2870 can be operated as a standalone board or as a modular system where the evaluation board is connected to a PC via an l C to USB interface board MICUSB Dongle EV Connecting the USB to I2C Adapter When interfacing the MIC2870 evaluation board with the MICUSB Dongle carefully match the GND pin of the evaluation board with the GND pin of the adapter as shown in Figure 3 the MICUSB Dongle will be upside down On the MIC2870 evaluation board the GND pin location is labeled on the left side of the board It is the first pin of the connecter receptacle JP1 The MICUSB Dongle has GND labeled on both sides of the adapter board Figure 3 MIC2870 Evaluation Board Interfaces with MICUSB Dongle EV adapter bottom side faces up Figure 4 Top Side of the Adapter with the Mini Slide Switch Toggled to Position September 24 2013 MIC2870 Eva2. Default Value D7 Access RAN Table 3 Flash Control Register 01h Name FTMR FTMR FTMR FEN FCUR FCUR FCUR FCUR mw mw nw RW nw 111 Table 4 Flash Safety Timer Setting FTMR 0 0000 Register Value D7 D5 of 01h Flash Timeout Duration ms 111 1250 110 1093 75 101 937 5 100 781 25 011 625 010 468 75 001 312 5 000 156 25 September 24 2013 5 Revision 1 2 Micrel Inc Table 5 Flash Mode Current Setting FCUR MIC2870 Evaluation Board Percentage of Maximum Register Value Current Per Channel mA Combined Current mA Current 96 D3 D0 of 01h Rerset 00 Rerset 00 100 0000 750 0 1500 0 90 0001 675 0 1350 0 80 0010 600 0 1200 0 70 0011 525 0 1050 0 63 0100 472 5 945 0 56 0101 420 0 840 0 50 0110 375 0 750 0 44 7 0111 335 3 670 5 39 8 1000 298 5 597 0 35 5 1001 266 3 532 5 31 6 1010 237 0 474 0 28 2 1011 211 5 423 0 25 1 1100 188 3 376 5 224 1101 168 0 336 0 20 1110 150 0 300 0 18 1111 135 0 270 0 Table 6 Torch Control Register 02h BIT D7 D6 D5 D4 D3 D2 D1 DO Name Reserved Reserved Fl TEN TCUR TCUR TCUR TCUR Access RO RO R W R W R W R W R W R W Default Value 0 0 0 0 0000 September 24 2013 6 Revision 1 2 Micrel Inc MIC2870 Evaluation Board Table 7 Torch Mode Current Setting TCUR
3. miEREL MIC2870 Evaluation Board 1 5A Synchronous Boost Flash LED Driver with C Interface General Description The MIC2870 is a high current high efficiency flash LED driver for one or two high brightness camera flash LEDs The LED driver current is generated by an integrated inductive boost converter with 2MHz switching frequency which allows the use of very small inductor and output capacitor These features make the MIC2870 an ideal solution for high resolution camera phone LED flash light driver applications MIC2870 supports two 750mA white LEDs WLEDs or a single 1 5A WLED configuration When two WLEDs are connected their currents are matched automatically MIC2870 operates in either flash or torch modes that can be controlled through either C interface or external pins The brightness in the flash and torch mode can be adjusted via two external resistors individually High speed mode 2 interface provides a simple control at a clock speed up to 3 4MHz to support most camera functions such as auto focus white balance and image capture Datasheets and support documentation are available on Micrel s web site at www micrel com Requirements The MIC2870 evaluation board requires a bench input power source that is adjustable from 2 7V to 5 0V and is able to deliver greater than 4 5A at 2 7V Precautions The evaluation board does not have reverse polarity protection Applying a negative voltage across t
4. Control Register 02h The torch mode enable torch mode current and flash inhibit are configurable via the torch control register The torch control register contains the TCUR bits bit and FI bit The TCUR bits set the torch mode current in 16 steps from 10096 down to 1896 of the maximum LED torch current which is set by the TRSET resistor The TEN bit has the same function as the TEN pin When the TEN bit is set the torch mode is enabled The FI bit has the same function as the Fl pin When the FI bit is set the flash mode current is reduced to the torch mode current setting The detail description of the bit names of all the bits and their assignment in the torch control register and their default values are shown in Table 6 The detail of the torch mode current setting is shown in Table 7 Revision 1 2 Micrel Inc Table 1 MIC2870 Register Map MIC2870 Evaluation Board Register Address Register Name Description 00h Master Control Status Chip Enable Control and Status Register 01h Flash Control Flash Mode Current Flash Mode Enable and Flash Timeout Control Register 02h Torch Control Torch Mode Current and Torch Mode Enable Control Register Table 2 Master Control Register 00h D7 D6 D5 D4 D3 D2 D1 DO Name Reserved Reserved Reserved Reserved ON LED_SHT LED_OP TSD Access R R R R RAN R R R Default Value 0 0 0 0 0 0 0 0 BIT
5. device Interface The timing diagram shows the communications required for write and read operations via the interface The black lines show master communications and the red lines show the slave communications During a write operation the master must drive SDA and SCL for all stages except the acknowledgement A shown in red which are provided by the slave MIC2870 SLAVE ADDRESS ADDRESS ex REGISTER 1011010 0 0 0 0 S WA A A P SLAVE REGISTER SLAVE DATA ADDRESS ADDRESS ADDRESS _ SDA i 1011010 010 0 SCL Figure 2 C Timing Example The read operation begins firstly with a data less write to select the register address from which to read Then a restart sequence is issued and then a read command followed by the data read The MIC2870 responds to a slave address of hex 0xB4 and OxB5 for write and read operations respectively or binary 1011010X where X is the read write bit The register address is eight bits wide and carries the address of the MIC2870 register to be operated upon Only the lower three bits are used September 24 2013 MIC2870 Evaluation Board Registers MIC2870 contains three 8 bit read write registers having an address from 00h to 02h for operation control as shown in Table 1 These registers are reset to their default values in power on reset POR event In other words they hold their previous contents when the chip is shutdown as
6. long as supply voltage is above 1 5V typical Master Control Status Register 00h The master control status register allows the MIC2870 to be enabled by the lC interface setting the ON bit high has the same effect as asserting EN pin The LED short bit LED is set if any or both of the LED is shorted to OUT while the LED open bit LED is asserted only when both LED are open circuit The thermal shutdown bit TSD is set when the junction temperature of the MIC2870 is higher than 160 C The bit names and assignment of all the bits in the master control status register and their default values are shown in Table 2 Flash Control Register 01h The flash mode enable flash safety timer and flash mode current are configurable via the flash control register The flash control register contains the FTMR bits FEN bit and FCUR bits The FTMR bits set the flash safety timer duration The FEN bit has the same function as the FEN pin When the FEN is set the flash mode is enabled The FCUR bits set the flash mode current in 16 steps from 10096 down to 1896 of the maximum LED flash current which is set by the FRSET resistor The detail description of the bit names of all the bits and their assignment in the flash control register and their default values are shown in Table 3 The details of flash timeout duration setting and flash mode current setting can be referred to Table 4 and Table 5 Torch
7. 104K TDK 0603ZD105KAT2A AVX C6 GRM188R61A105KA61D Murata Ceramic Capacitor 1uF 10V X5R 0603 1 C1608X5R1A105K080AC TDK T CDRH4D28CLDNP 1ROPC Sumida Inductor 1H 3 0A 14mQ L5 1mm x W5 1mm x H3 0mm LQH44PN1RONPOL Murata Inductor 1uH 2 45A 36mO L4 0mm x W4 0mm H1 65mm R1 R2 CRCWO06034K70FKEA Vishay Dale Resistor 4 7 196 1 10W 0603 2 R3 R4 103 Panasonic Resistor 10kQ 0 1 1 10W 0603 2 i CRCW060310KOFKEA Vishay Dale Resistor 10 1 1 10W 0603 4 2112 SML LXL99UWC TR 5 Lumex LED SQ 5W COOL WHT 6000K SMD 1901 2ER103CW06000002 Edison Opto LED 3W COOL WHT 6000K SMD 210Im U1 MIC2870YFT Micrel Inc 1 5A Synchronous Boost Flash LED Driver with Interface 1 Notes 1 AVX www avx com 2 TDK www tdk com 3 Murata www murata com 4 Sumida www sumida com 5 Vishay www vishay com 6 Panasonic www panasonic com 7 Lumex www lumex com 8 Edison Opto www edison opto com 9 Micrel Inc www micrel com September 24 2013 12 Revision 1 2 Micrel Inc MIC2870 Evaluation Board PCB Layout Recommendations 4 72354 377 mil lt 653 597 mil Top Layer 354 377 mi 71653 597 mi Bottom Layer September 24 2013 13 Revision 1 2 Micrel Inc MIC2870 Evaluation Board MICREL INC 2180 FORTUNE DRIVE SAN JOSE CA 95131 USA TEL 1 408 944 0800 FAX 1 408 474 1000 WEB http w
8. EV The SW1 should be toggled to the position as shown in Figure 4 6 Open the MIC2870 evaluation software in Programs under the Start Menu Revision 1 2 Micrel Inc Evaluation Software The MIC2870 evaluation software graphic user interface GUI is shown in Figure 5 and Figure 6 When the evaluation software is just started it is default in offline mode as shown on the right of the top menu bar in Figure 5 The offline mode is only for running the software without the communication or connection with the MIC2870 evaluation board To control the MIC2870 evaluation board with the software GUI the user firstly has to click the Test button If the connection from the PC to the dongle and then to the MIC2870 EVB is fine as instructed in Connecting the USB to I C Adapter section and in steps 4 and 5 in the Getting Started section the Target OK will be shown up at the status bar at the bottom of the GUI as shown Figure 5 If the connection is not good the Target Not Detected will be shown up at the status bar and the user has to check with the cable connections before proceeding to the next step When the Target OK status is shown the user can click on the Offline Mode at the menu bar to change it to Direct Editing Mode When the Direct Editing Mode is shown up at the top menu bar and the Direct Editing Mode Active is indicated at the status bar as shown in Figure 6 the software GUI allows the user to contr
9. e enabled or disabled by software through I C interface 4 Enable Disable the flash mode The FEN TP2 upper pin is the flash mode enable pin A low to high transition at this pin initiates the flash mode and the flash mode timer Setting a jumper at TP2 can connect FEN to VIN through a resistor If this pin is left floating it is pulled down internally by a built in 14A current source when the device is enabled Alternatively the flash mode can be enabled or disabled by software through interface Ordering Information Part Number Description MIC2870YFT EV MIC2870 Evaluation Board MICUSB Dongle EV Serial Programmer Board Micrel Inc 2180 Fortune Drive San Jose CA 95131 USA tel 1 408 944 0800 fax 1 408 474 1000 http www micrel com September 24 2013 Revision 1 2 Micrel Inc MIC2870 Evaluation Board Getting Started Continued 5 Enable Disable flash inhibit The FI TP3 upper pin is the flash inhibit pin When this pin is high in flash mode both LED1 D1 and LED2 D2 currents are changed from the flash mode current level to the torch mode current level When this pin is low both LED1 D1 and LED2 D2 currents are changed from torch mode current level back to the original flash mode current level Setting a jumper at TP3 can connect FI to VIN through a resistor If this pin is left floating it is pulled down internally by a built in 1pA current so
10. he VIN terminal to GND terminal may damage the device The MIC2870 evaluation board is tailored for a Li ion range input supply voltage It should not exceed 5 0V on the input Getting Started 1 Connect external supply to the VIN terminals Apply desired input voltage to the VIN J1 and ground J2 terminals of the evaluation board paying careful attention to polarity and supply range 2 7V to 5 0V An ammeter may be placed between the power supply and the input terminal of the evaluation board Ensure that the supply voltage is monitored at the input terminals The ammeter and or power lead resistance can reduce the voltage supplied to the input 2 Enable Disable the MIC2870 The MIC2870 evaluation board has an enable EN pin 45 The MIC2870 is in standby mode when the EN pin is asserted high Setting a jumper at TP1 can connect the EN pin to VIN through a pull high resistor If this pin is driven low for more than 1s the IC is shutdown This pin is pulled down by an internal resistor Alternatively the IC can be enabled or disabled by software through interface 3 Enable Disable the torch mode The TEN J3 is the torch mode enable pin When this pin is high the torch mode is initiated Setting a jumper at TP4 can connect TEN pin to VIN through a resistor If this pin is left floating it is pulled down internally by a built in 1 current source when the device is enabled Alternatively the torch mode can b
11. lt indication will be shown at the bottom of the control panel if the register polling is enabled and fault conditions are detected The current detected fault value can be cleared by clicking the Clear button Setting of C Data Rate The data rate of the I C communication can be set at the pull down menu from the IC menu at the top menu bar as shown in Figure 7 User can set the data rate to 100kbps 400kbps or 3 4Mbps from the pull down menu Revision 1 2 Micrel Inc File Link 2 Help Destination Address Q5A b 1011010X 3E Read Address Hex 00 01 02 Data Hex 00 00 00 Read Only O O O Offline Mode Register Polling Period ns 500 Host comms are in offline mode to allow the GUI controls to write directly to hardware press the test button to establish communications and then use Direct Editing mode in the Link menu MIC2870 Evaluation Board Special Effects delayins 200 m med wm Fault No Current Fault No Previous Faults MIC2870 0x5A Data Rate 100k bps Target OK Figure 5 MIC2870 Evaluation Software GUI in Offline Mode File Link 2 Help Destination Address Ox 5A Ob 1011010 Direct Editing Mode Register Polling Period ms 500 Enable Address Hex 00 01 0 Data Hex 00 FO Read Ony 7 7 E MIC2870 Control Flash Brightness Control Rese
12. luation Board MIC2870 Evaluation Software The MIC2870 evaluation software provides a graphic user interface GUI to program the MIC2870 evaluation board A complete application note on the installation and operation of the evaluation software and the USB adapter user manual can be downloaded from Micrel s web site at www micrel com The evaluation software can read and write to registers inside the MIC2870 IC device via for enabling or disabling the device torch mode flash mode and flash inhibit changing the WLEDs brightness in torch mode and flash mode changing the flash safety timer duration enabling disabling breath and strobe special effects and reporting fault status Getting Started 1 Download the MIC2870 evaluation software and run the setup exe file This step may take some time and require an internet connection to update the computer to NET Framework 3 5 2 Install the MICUSB Dongle EV driver from FTDI Double click on the file CDM20828 Setup exe The latest driver can be downloaded from the FTDI website www ftdichip com 3 After installing the driver locate the virtual COM port created by the FTDI driver in the Device Manager Menu under Ports COM amp LPT The corresponding port will have FTDI listed as the manufacturer 4 Connect the MIC2870 evaluation board to the PC via the MICUSB Dongle EV Power the MIC2870 evaluation board VIN input 5 Setthe mini slide switch SW1 on the MICUSB Dongle
13. nd Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale 2013 Micrel Incorporated September 24 2013 14 Revision 1 2
14. ol the operation of the MIC2870 evaluation board Introduction to the GUI Panel At the left side of the GUI panel user can check with the MIC2870 registers information and perform read and write operation to the IC registers At the middle of the GUI panel user can click the Enable option to enable the register polling September 24 2013 MIC2870 Evaluation Board At the right side of the GUI panel which is the MIC2870 Control panel user can perform the following MIC2870 operation 1 Check or uncheck the Enabled option to enable or disable the MIC2870 device 2 Change the flash safety timer duration setting from 0 to 7 which corresponding to 8 options from 156ms to 1250ms Please refer to Table 4 for details 3 Adjust the flash brightness with the slide bar from 100 to 18 of the maximum LED current in flash mode in 16 steps The maximum is on the left and the minimum is on the right 4 Fire flash or reset flash by clicking the flash mode enable button 5 Check or uncheck flash inhibit option to enable or disable the flash inhibit function 6 Adjust the torch brightness with the slide bar from 100 to 18 of the maximum LED current in torch mode in 16 steps The maximum is on the left and the minimum is on the right 7 Setorreset torch by clicking on the torch mode enable button 8 Click the Breath button Strobe button and set delay time options for special effects demonstration 9 Fau
15. t Flash Torch Brightness Control Toggle Torch Special Effects savino 20 Ei 2 79 Fault Value No Previous Faults MIC2870 0x5A Data Rate 0k bps Direct Editing Mode Active Figure 6 MIC2870 Evaluation Software GUI in Direct Editing Mode File Link Help Direct Editing Mode 100kbps Search DC Slave 400kbps 34Mbps Data Hex 00 FO 00 Read Ony 7 E E MIC2870 Control Flash Brightness Control Torch Brightness Control Toggle Torch Special Effects Breath delay ms 200 70 70 Fault Value Clear No Previous Faults MIC2870 5A Data Rate 0k bps Direct Editing Mode Active Figure 7 Setting Data Rate from Pulldown Menu September 24 2013 10 Revision 1 2 Micrel Inc MIC2870 Evaluation Board Evaluation Board Schematic U1 MIC2870YFT PGND PGND ePAD FRSET TRSET September 24 2013 11 Revision 1 2 Micrel Inc Bill of Materials MIC2870 Evaluation Board Item Part Number Manufacturer Description Qty 0603ZD475KAT2A AVX C3 3 Ceramic Capacitor 4 7uF 10V X5R 0603 1 C1608X5R1A475K080AC TDK 0603ZD225KAT2A AVX C4 GRM188R61A225KE34D Murata Ceramic Capacitor 2 2uF 10V X5R 0603 1 C1608X5R1A225K080AC TDK 06033D104KAJ2A AVX C5 GRM188R61C104KA01D Murata Ceramic Capacitor 0 1uF 25V X5R 0603 1 C1608X5R1E
16. ter The flash safety timeout feature automatically shuts down the flash current if the flash mode is enabled for an extended period of time Refer to the Flash Safety Timer setting in Table 4 September 24 2013 MIC2870 Evaluation Board The flash inhibit Fl pin can be used to synchronize the flash current to a handset GSM pulse event to prevent excessive battery droop When FEN and FI pins are both high the flash mode current is limited to the torch mode current setting The FI Pin is also functional when the flash mode current is enabled through the C flash register Torch Mode The maximum torch mode level can be adjusted through an external resistor connecting to the TRSET pin according to Equation 2 7500 Eq 2 4RrnsET ILED MAX Alternatively the default maximum value of 187 5mA per channel is used when the TRSET pin is grounded The torch mode operation is activated by asserting the TEN pin high or by setting the C torch register address 02h for the desired duration The torch mode current is terminated when the TEN pin is brought low and the C torch register is cleared Like the flash mode current the torch mode current can be set to a fraction of the maximum torch mode level either default or set by the TRSET resistor by selecting the desired torch current level percentage in the torch register Address 02h through the interface The torch current is the product of the maximum torch c
17. urce when the device is enabled 6 Graphic user interface support Graphical user interface software can be used with the MICUSB Dongle EV allowing configuration and testing of the MIC2870 with a standard computer For more detail refer to the Evaluation Software section September 24 2013 2 Revision 1 2 Micrel Inc Evaluation Board Description Figure 1 MIC2870 Evaluation Board Flash Mode The maximum current level in the flash mode is 750mA per channel This current level can be adjusted through an external resistor connecting to the FRSET pin according to Equation 1 7500 lLED MAX Raa FRSET Eq 1 Alternatively the default maximum value of 750mA per channel is used when the FRSET pin is grounded The flash mode current can be initiated at the preset FRSET brightness level by asserting FEN pin high or by setting the flash control register address 01h for the desired flash duration subjected to the flash safety timeout setting The flash mode current is terminated when the FEN pin is brought low and the C flash register is cleared Flash mode current can be adjusted to a fraction of the maximum flash mode level either default or set by the FRSET resistor by selecting the desired flash current level percentage in the flash control register Address 01h through the C interface The flash current is the product of the maximum flash current setting and the percentage selected in the flash regis
18. urrent setting and the percentage selected in the torch register Overvoltage Protection When the output voltage rises above the OVP threshold the MIC2870 is turned off automatically to avoid permanent damage to the IC Open Circuit Detection The open circuit detector OCD is active only when the LED current regulator is turned on When the external LED is missing or fails open the LED1 2 pin voltage is pulled to near the ground potential by the internal current sink If both LEDs are open or missing the open circuit detector would force the boost regulator and LED current regulator to turn off The MIC2870 will try to turn on the boost regulator and LED current regulator again after a 100ms timeout However in most practical cases the boost output voltage would rise above the OVP threshold when both LED channels have an open fault The OVP function would cause the MIC2870 to shut down Revision 1 2 Micrel Inc Short Circuit Detection Like the open circuit detector the short circuit detector is active only when the current regulator is turned on If either one or both of the external LEDs fail as a short the short circuit detector would force the MIC2870 to turn off The MIC2870 will try to turn on the boost regulator and LED current regulator again after a 100ms timeout If the short condition persists the whole cycle repeats again Prolonged operation in short circuit condition is not recommended as it may damage the
19. ww micrel com Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet This information is not intended as a warranty and Micrel does not assume responsibility for its use Micrel reserves the right to change circuitry specifications and descriptions at any time without notice No license whether express implied arising by estoppel or otherwise to any intellectual property rights is granted by this document Except as provided in Micrel s terms and conditions of sale for such products Micrel assumes no liability whatsoever and Micrel disclaims any express or implied warranty relating to the sale and or use of Micrel products including liability or warranties relating to fitness for a particular purpose merchantability or infringement of any patent copyright or other intellectual property right Micrel Products are not designed or authorized for use as components in life support appliances devices or systems where malfunction of a product can reasonably be expected to result in personal injury Life support devices or systems are devices or systems that a are intended for surgical implant into the body or b support or sustain life and whose failure to perform can be reasonably expected to result in a significant injury to the user A use or sale of Micrel Products for use in life support appliances devices or systems is a Purchaser s own risk a
Download Pdf Manuals
Related Search