Brightness and Color Control Unit XMC microcontrollers September 2016
Agenda 1 2 3 4 5 6 7 Overview Key feature: Automatic high frequency brightness modulation Key feature: Automatic exponential dimming and linear intensity change Key feature: Controlled rate of switching System integration Application example Additional features 2
Agenda 1 2 3 4 5 6 7 Overview Key feature: Automatic high frequency brightness modulation Key feature: Automatic exponential dimming and linear intensity change Key feature: Controlled rate of switching System integration Application example Additional features 3
Brightness and Color Control Unit Highlights Designed to automatically control the dimming level and color of multichannel LED lamps Requires little user code Transitions appear natural to the human eye Key features Automatic high frequency brightness modulation (PDM) Automatic exponential dimming and linear intensity change Controlled rate of switching Customer benefits Completely flicker free; no visible or intrasaccadic flicker; 12-bit resolution Dimming level or color changes appear smooth and natural to the human eye Compatible with a wide range of high power LED drivers 4
Agenda 1 2 3 4 5 6 7 Overview Key feature: Automatic high frequency brightness modulation Key feature: Automatic exponential dimming and linear intensity change Key feature: Controlled rate of switching System integration Application example Additional features 5
- Automatic high frequency brightness modulation (PDM) High frequency brightness modulation ON-OFF dimming signal generated by a 12-bit - modulator in every channel Adjustable bit rate; 40-1000 kbps recommended no visible flicker or shimmer; no steady or intrasaccadic flicker (<3 khz) that may cause neurological effects Automatic light quality control Built-in flicker watchdog to eliminate flicker even at very low brightness levels Dimming Engine t Linear Walker 12 Dimming Level Intensity Brightness?-? Modulator 12 12 1 Modulated bit stream to LED channel 6
Agenda 1 2 3 4 5 6 7 Overview Key feature: Automatic high frequency brightness modulation Key feature: Automatic exponential dimming and linear intensity change Key feature: Controlled rate of switching System integration Application example Additional features 7
Automatic exponential dimming Automatic gradual brightness change Brightness level changes along an exponential curve The change appears natural, the human eye can adapt comfortably DIMMING LEVEL 100% Clock Pre-Divider DTTz.DIMDIV Target Dimming Level DLSz.TDLEV Dimming Engine Dimming Level DLz.DLEV Invisible dimming steps Dithering can be applied at low dimming levels if transition is slow TIME 20480 clocks 8
Automatic linear intensity change Automatic smooth color change Selected channels continuously change their intensity for a predetermined duration The respective targets are reached at the same time (variable clock base) Straight transition in the orthogonal color space (e.g. RGB) 9
Agenda 1 2 3 4 5 6 7 Overview Key feature: Automatic high frequency brightness modulation Key feature: Automatic exponential dimming and linear intensity change Key feature: Controlled rate of switching System integration Application example Additional features 10
Controlled rate of switching It takes time for the LED current to stabilize Longer in switched-mode systems Longer in high-power systems PDM has higher switching rate Group similar bits together at higher brightness levels To make ON-times longer To lower the average switching rate No effect on brightness Too short unpacked 0 0 1 0 0 0 1 0 0 0 1 0 0 0 0 1 0 0 0 1 packed 0 0 1 1 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 1 Acceptable hold time 11
Agenda 1 2 3 4 5 6 7 Overview Key feature: Automatic high frequency brightness modulation Key feature: Automatic exponential dimming and linear intensity change Key feature: Controlled rate of switching System integration Application example Additional features 12
System integration ACMP OUT OUT SCU ERU SR2 IOUT IN TRAP PORTS TRIG SR0 Target applications Intelligent lighting Power conversion PORTS CCU4 MCI IN1 IN2 IN3 CCU8 VADC BGREQ G0REQ G1REQ NVIC XMC1100 XMC1200 XMC1300 The primary function of is to provide automatic dimming signals on port pins for external LED drivers. (OUT) Two trigger signals can start ADC conversions to take noise-free measurements on the LED channels. (TRIG) The dimming signals can also be routed to CCU4 or CCU8 which can directly drive the LED current control circuitry. (OUT) Trap state occurs when there is an external emergency (e.g. short circuit). This information can be routed to directly from pins, via SCU or ERU. During trap, the outputs immediately go to a predetermined safe passive level. (TRAP) The output of the analog comparators can be used as an asynchronous gating signal to channels for fast control loops. (IN) 13
Agenda 1 2 3 4 5 6 7 Overview Key feature: Automatic high frequency brightness modulation Key feature: Automatic exponential dimming and linear intensity change Key feature: Controlled rate of switching System integration Application example Additional features 14
RGB lamp control with external linear drivers Exponential Dimming Engine Dimming Level In brief X X X Blue Intensity Blue Brightness Green Intensity Green Brightness Red Intensity Red Brightness Linear Walker?? modulator Linear Walker?? modulator Linear Walker?? modulator LED Driver Automatic color control, smooth color change Automatic dimming control, natural changes in dimming level Easy on the human eye Flicker elimination and smoothened dimming steps EN LED Driver EN LED Driver EN Overview provides color control with 12-bit precision. Color transitions can be immediate or gradual by a linear walk. Lamp dimming level is separately controlled from lamp color, also with 12-bit precision. Dimming level can change exponentially over time to appear natural to the human eye. Flickering due to low switching rate and visible steps due to slow dimming at low intensity levels can be automatically eliminated. 15
RGB lamp control with external linear drivers X Blue Intensity Blue Brightness Linear Walker?? modulator LED Driver EN Exponential Dimming Engine Dimming Level X Green Intensity Green Brightness Linear Walker?? modulator LED Driver EN X Red Intensity Red Brightness Linear Walker?? modulator LED Driver EN RGB lamp control: Detailed block diagram 16
RGB lamp control with switched-mode current control Exponential Dimming Level Dimming Level In brief X Blue Intensity Green Intensity Green Brightness Red Intensity Linear Walker Blue?? X Brightness modulator Linear Walker?? modulator Linear Walker Red?? X Brightness modulator CCUx slice ACMP CCUx slice CCUx slice Automatic smooth color and dimming control Easy on the human eye FFlicker elimination and smoothened dimming steps Low-cost high-quality multi-channel DCDC LED driver solution ACMP ACMP ref ref ref Overview provides color control with 12-bit precision. Color transitions can be immediate or gradual by a linear walk. Lamp dimming level is separately controlled from lamp color, also with 12- bit precision. Dimming level can change exponentially over time to appear natural to the human eye. Flickering due to low switching rate and visible steps due to slow dimming at low intensity levels can be automatically eliminated. Fast current control possible by wellinterconnected switching and analog peripherals. 17
RGB Lamp Control with switched-mode current control Blue Intensity Linear Walker X Blue Brightness?? modulator CCUx slice Exponential Dimming Engine Dimming Level X Green Intensity Green Brightness Linear Walker?? modulator ACMP CCUx slice ref Red Intensity Linear Walker ACMP ref X Red Brightness?? modulator CCUx slice ACMP ref RGB lamp control: Detailed block diagram 18
Agenda 1 2 3 4 5 6 7 Overview Key feature: Automatic high frequency brightness modulation Key feature: Automatic exponential dimming and linear intensity change Key feature: Controlled rate of switching System integration Application example Additional features 19
Synchronized sampling trigger modes (1/2) Trigger mode 0 Trigger pulse generated on both lines when rising/falling edge occurs on any output Sample all channels when any trigger occurs State of outputs stored in LTCHOL High ADC load 1 2 6 8 Trig 0 Trig 1 20
Synchronized sampling trigger modes (2/2) Trigger mode 1 s can generate trigger in a round robin manner on one of the two outputs Sample only one channel at a time ADC queues have to be set up properly (order, trigger, auto-refill) Low ADC load Inintialized Group 0 QUEUE Initialized Group 1 QUEUE 1 2 6 8 Trig 0 Trig 1 3 2 4 T T T R R R 5 T R 21
Multi-ch. lamp control with ext. lin. drivers + ADC trig. Dimming Engine Trigger XMC1000 In brief ADC LED driver LED driver LED driver LED driver Automatic dimming control, natural changes in dimming level LED driver compatibility, controlled switching rate Support for timed channel measurements Overview provides lamp dimming level control with 12-bit precision. The dimming level can change exponentially over time to appear natural to the human eye. The rate of switching of the output signals can be tightly controlled to ensure minimum hold times for high power external LED drivers. provides trigger signals to the ADC to achieve synchronized sampling. The output signals can be phase shifted relative to each other to smoothen the load on the common voltage rail. 22
Multi-ch. lamp control with ext. lin. drivers + ADC trig. XMC 1000 LED driver LED driver Dimming Engine LED driver Trigger LED driver ADC Street lamp control: Detailed block diagram 23
Flicker watchdog Flicker happens when there are long periods of 0 bits Flicker watchdog is useful at low brightness levels Inserts 1 bit when there are long periods of 0 bits Trade-off: pulse insertion limits minimum brightness Inserted 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 24
Pseudo-DAC only available on AB step Analog voltage level on connected pins 12-bit precision Can be used as comparator reference voltage The pins with analog signal level can be used as input pins to other modules (e.g. internal analog comparators) Overridden hardware pull-up and pull-down control For small capacitors it is recommended to have a high frequency bit clock 25
Pseudo-DAC only available on AB step DAC functionality available on many pins Ch 0 Ch 1 Ch 2 Ch 3 Ch 4 Ch 5 Ch 6 Ch 7 Ch 8 PORT HW Control PORT HW Control PORT HW Control PORT HW Control PORT HW Control PORT HW Control PORT HW Control PORT HW Control PORT HW Control P2.2 P2.0 P2.8 P1.0 P2.6 P1.1 P1.2 P2.10 P1.3 P2.11 P1.4 P2.1 P1.5 P2.9 P1.6 P2.4 P2.7 26
General information For latest updates, please refer to: www.infineon.com/xmc1000 For support: http://www.infineonforums.com/forums/8-xmc-forum 27
Support material Collaterals and Brochures Technical Material Product Briefs Selection Guides Application Brochures Presentations Press Releases, Ads Application Notes Technical Articles Simulation Models Datasheets, MCDS Files PCB Design Data www.infineon.com/xmc www.infineon.com/xmc Kits and Boards DAVE TM Software and Tool Ecosystem Videos Technical Videos Product Information Videos Infineon Media Center XMC Mediathek Contact Forums Product Support Infineon Forums Technical Assistance Center (TAC) 28
Disclaimer The information given in this training materials is given as a hint for the implementation of the Infineon Technologies component only and shall not be regarded as any description or warranty of a certain functionality, condition or quality of the Infineon Technologies component. Infineon Technologies hereby disclaims any and all warranties and liabilities of any kind (including without limitation warranties of noninfringement of intellectual property rights of any third party) with respect to any and all information given in this training material.
30