MPQ7221 Tail Lamp Reference Design
Multi-Channel LED Driver for Automotive Systems
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1 Overview
1.1 Description
The tail lamp dynamic requirement in automotive lighting applications is becoming increasingly demanding. This reference design showcases a holistic tail lamp proposal, including a stop lamp (SL), turn lamp (TL), and side mark lamp (SML), which uses three MPQ7221 devices to drive the LED strings.
The MPQ7221 is a 16-channel current sink LED driver that operates across a wide 4.5V to 16V input voltage (VIN) range. The LED current (ILED) of each channel is set by an external current-setting resistor, with a maximum current up to 80mA. The MPQ7221 integrates an I2C interface, where 10 different I2C addresses can be configured via an external resistor to achieve a rich dynamic effect.
The MPQ7221 is available in a QFN-24 (4mmx4mm) package with wettable flanks, and is AEC-Q100 qualified.
1.2 Features
- Wide 4.5V to 16V Input Voltage (VIN) Range
- 16 Channels, 80mA/Channel Max
- LED Current (ILED) Configured by an External Resistor
- 6-Bit Analog Dimming for Each Channel
- 12-Bit Pulse-Width Modulation (PWM) Dimming for Each Channel
- Selectable PWM Dimming Frequency (fPWM): 220Hz, 250Hz, 280Hz, or 330Hz
- Refresh Signal Output
- I2C Interface
- 10 Addresses, Configurable via an External
Resistor - Configurable ILED Slew Rate
- 40µs Phase Shift
Threshold
with Wettable Flanks
Figure 1: EVQ7221-TL-00A Tail Lamp Control Board and Tail Lamp Board
1.3 Applications
- Automotive Power Systems
- Industrial Systems
- Automotive Taillights
- Automotive Turning Lights
2 Reference Design
2.1 Block Diagram
This reference design includes one buck converter (MPQ4323), one low-dropout (LDO) regulator (MPQ2013A), three LED drivers (MPQ7221), and one microcontroller unit (MCU) (KEA8) (see Figure 2). VIN is typically 12V, and the three MPQ7221 devices independently drive three different lamp types. The MCU defines the dynamic performance.
Figure 2: Block Diagram
2.2 Related Solutions
This reference design is based on the following MPS solutions:
Table 1: MPS Solutions
| MPS Integrated Circuit | Description |
| MPQ2013A | 40V, 150mA, low quiescent current linear regulator, AEC-Q100 qualified |
| MPQ4323 | 36V, 3A, low quiescent current, synchronous step-down converter, AEC-Q100 qualified |
| MPQ7221 | 16-channel, 80mA/ch, LED driver with separated PWM analog dimming and I2C interface, AEC-Q100 qualified |
2.3 System Specifications
Table 2: System specifications
| Parameter | Specification |
| Input voltage (VIN) range | 5VDC to 36VDC |
| Output LEDs | 16 LEDs for stop lamp (SL), 14 LEDs for turn lamp (TL),16 LEDs for side mark lamp (SML) |
| Output current (IOUT) | 50mA/ch for SL, 40mA/ch for TL, 8mA/ch for SML |
3 Design
3.1 Schematic
Figure 3: Control Board Schematics
Figure 4: Lamp Board Schematics
3.2 BOM
Table 3: Control Board Bill of Materials
| Qty | Ref | Value | Description | Package | Manufacturer | Manufacturer PN |
| 2 | C1, C4 | NS | ||||
| 1 | C2 | 1µF | Ceramic capacitor, 100V, X7R | 1210 | Murata | GRM32ER72A105KA01L |
| 4 | C3, C404, C504, C604 | 4.7µF | Ceramic capacitor, 25V, X7R | 1210 | TDK | C3225X7R1E475M |
| 8 | C301, C302, C401, C402, C501, C502, C601, C602 | 4.7µF | Ceramic capacitor, 50V, X7S | 0805 | Murata | GRM21BC71H475KE11L |
| 5 | C303, C304, C307, C310, C311 | 0.1µF | Ceramic capacitor, 50V, X7R | 0603 | Murata | GRM188R71H104KA93D |
| 1 | C305 | 1µF | Ceramic capacitor, 16V, X7R | 0603 | Murata | GRM188R71C105KA12D |
| 2 | C308, C309 | 22µF | Ceramic capacitor, 10V, X5R | 0805 | Murata | GRM219R61A226MEA0D |
| C306, C403, C503, C603, CIN1, CIN2 | NS | |||||
| 2 | CIN3, CIN4 | 1nF | Ceramic capacitor, 50V, C0G | 0603 | Murata | GRM1885C1H102JA01D |
| 2 | CIN5, CIN6 | 47nF | Ceramic capacitor, 100V, X7R | 0805 | Murata | GRM21BR72A473KA01L |
| 2 | CIN7, CIN8 | 2.2µF | Ceramic capacitor, 50V, X7R | 0805 | Murata | CGA4J3X7R1H225KT000N |
| 1 | CIN9 | 22µF | Aluminum polymer capacitor, 50V | SMD | Panasonic | EEHZC1H220P |
| 3 | CN1_SL, CN2_TL, CN3_SML | 1mm | Connector, 2x10-pin, 90° | DIP | Custom | |
| 3 | CN1_SL, CN2_TL, CN3_SML | 1mm | Wiring harness, 2x10-pin | DIP | Custom | |
| 1 | D1 | 60V | Schottky diode, 3A | SMA | Diodes, Inc. | B360A-13-F |
| 1 | D2 | 33V | TVS diode | SMB | Vishay | SMBJ33AHE3_A/H |
| 3 | F401, F501, F601 | 63V | Fuse, 2A | 1206 | Bei | 0685-2000-01 |
| 1 | L1 | 240nH | Inductor, 19mΩ, 6.6A | SMD | TOKO, Inc. | DFE201612E-R24M |
| 1 | L2 | 1µH | Inductor | SMD | Coilcraft | XEL4020-102MEB |
| 1 | L3 | 2.2µH | Inductor | SMD | Coilcraft | XEL4030-222MEB |
| 14 | JP1, JP401, JP402, JP501, JP502, JP601, JP602, R3, R5, R304, R401, R501, R601, R405 | 0Ω | Film resistor, 5% | 0603 | Yageo | RC0603JR-070RL |
| 4 | R1, R2, R4, R8 | 10kΩ | Film resistor, 1% | 0603 | Yageo | RC0603FR-0710KL |
| 9 | R301, R305, R306, R402, R403, R502, R503, R602, R603 | 100kΩ | Film resistor, 1% | 0603 | Yageo | RC0603FR-07100KL |
| 1 | R303 | 16.2kΩ | Film resistor, 1% | 0603 | Yageo | RC0603FR-0716K2L |
| 1 | R307 | 21.5kΩ | Film resistor, 1% | 0603 | Yageo | RC0603FR-0721K5L |
| 1 | R406 | 24kΩ | Film resistor, 1% | 0603 | Yageo | RC0603FR-0724KL |
| 1 | R505 | 3kΩ | Film resistor, 1% | 0603 | Yageo | RC0603FR-073KL |
| 2 | R506, R605 | 30kΩ | Film resistor, 1% | 0603 | Yageo | RC0603FR-0730KL |
| 1 | R606 | 150kΩ | Film resistor, 1% | 0603 | Yageo | RC0603FR-07150KL |
| 1 | R7 | 30.9kΩ | Film resistor, 1% | 0603 | Yageo | RC0603FR-0730K9L |
| R6, R302, R404, R504, R507, R508, R604 | NS | |||||
| 6 | GND4, GND5, GND6, RFSH/FLT, RFSH/FLT, RFSH/FLT6 | 1mm | Golden pin | DIP | Custom | |
| 1 | INPUT | 2.54mm | Connector, 2-pin | SMD | Custom | |
| 1 | J1 | 2.54mm | Test pin, 1x5-pin | DIP | Custom | |
| 1 | J2 | 2.54mm | Test pin, 1x6-pin | DIP | Custom | |
| 1 | J3 | 2.54mm | Test pin, 1x9-pin | DIP | Custom | |
| 2 | GND, SW1 | 12V | Button | DIP | Custom | KAN3511-0431C |
| 1 | U1 | 5.5V | Microcontroller unit | TSSOP-16 | NXP Semiconductors | S9KEAZN8AMTG |
| 1 | U2 | MPQ2013A | Low-IQ linear regulator, AEC-Q100 qualified | QFN-8 (3mm x 3mm) | MPS | MPQ2013AGG |
| 1 | U3 | MPQ4323 | 42V load dump, sync step-down converter, AEC-Q100 qualified | QFN-12 (2mm x 3mm), QFN-12 (3mm x 4mm) | MPS | MPQ4323GDE-AEC1 |
| 3 | U4, U5, U6 | MPQ7221 | 16-ch LED driver, AEC-Q100 qualified | QFN-24 (4mm x 4mm) | MPS | MPQ7221GRE-AEC1 |
Table 4: Lamp Board Bill of Materials
| 3 | CN1_SL, CN2_TL, CN3_SML | 1mm | Connector, 2x10-pin, 90° | DIP | Custom | |
| 16 | LED1, LED2, LED3, LED4, LED5, LED6, LED7, LED8, LED9, LED10, LED11, LED12, LED13, LED14, LED15, LED16 | 2.15V | Amber LED | SMD | ams OSRAM | LA E67F-BADB-24-3A5A |
| 14 | LED17, LED18, LED19, LED20, LED21, LED22, LED23, LED24, LED25, LED26, LED27, LED28, LED29, LED30 | 2.15V | Yellow LED | SMD | ams OSRAM | LY E67F-ABCA-35-3B5A |
| 16 | LED31, LED32, LED33, LED34, LED35, LED36, LED37, LED38, LED39, LED40, LED41, LED42, LED43, LED44, LED45, LED46 | 2.15V | Red LED | SMD | ams OSRAM | LR E67F-ABCB-1-1 |
| 5 | CN1_SL, CN2_TL, CN3_SML | 1mm | Wiring harness, 2x10-pin | DIP | Custom |
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