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  • LP8868-Q1 Automotive Multi-Topology LED Driver with Inductive Fast Dimming

    • SLVSH98A July   2023  – November 2023 LP8868U-Q1 , LP8868V-Q1 , LP8868W-Q1 , LP8868X-Q1 , LP8868Y-Q1 , LP8868Z-Q1

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  • LP8868-Q1 Automotive Multi-Topology LED Driver with Inductive Fast Dimming
  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4  Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Adaptive Off-Time Current Mode Control
        1. 7.3.1.1 Switching Frequency Settings
        2. 7.3.1.2 Spread Spectrum
      2. 7.3.2 Setting LED Current
      3. 7.3.3 Internal Soft Start
      4. 7.3.4 Dimming Mode
        1. 7.3.4.1 PWM dimming
        2. 7.3.4.2 Analog dimming
        3. 7.3.4.3 Hybrid Dimming
        4. 7.3.4.4 Flexible Dimming
      5. 7.3.5 Undervoltage Lockout
      6. 7.3.6 Fault Protection
      7. 7.3.7 Thermal Foldback
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 LP8868XQDMTRQ1 12-V Input, 1-A Output, 8-piece LED With Boost Topology
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Inductor Selection
          2. 8.2.1.2.2 Input Capacitor Selection
          3. 8.2.1.2.3 Output Capacitor Selection
          4. 8.2.1.2.4 Sense Resistor Selection
          5. 8.2.1.2.5 Other External Components Selection
        3. 8.2.1.3 Application Curves
      2. 8.2.2 LP8868YQDMTRQ1 12-V Input, 1-A Output, 5-piece LED With Buck-Boost Topology
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Inductor Selection
          2. 8.2.2.2.2 Input Capacitor Selection
          3. 8.2.2.2.3 Output Capacitor Selection
          4. 8.2.2.2.4 Sense Resistor Selection
          5. 8.2.2.2.5 Other External Components Selection
        3. 8.2.2.3 Application Curves
      3. 8.2.3 LP8868ZQDMTRQ1 12-V Input, 2-A Output, 1-piece LED With Buck Topology
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
          1. 8.2.3.2.1 Inductor Selection
          2. 8.2.3.2.2 Input Capacitor Selection
          3. 8.2.3.2.3 Output Capacitor Selection
          4. 8.2.3.2.4 Sense Resistor Selection
          5. 8.2.3.2.5 Other External Components Selection
        3. 8.2.3.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
  13. IMPORTANT NOTICE

Package Options

Mechanical Data (Package|Pins)
  • DMT|14
    • MPSS087B
Thermal pad, mechanical data (Package|Pins)
  • DMT|14
    • QFND638
Orderable Information
  • slvsh98a_oa
  • slvsh98a_pm
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Data Sheet

LP8868-Q1 Automotive Multi-Topology LED Driver with Inductive Fast Dimming

1 Features

  • AEC-Q100 Qualified for automotive applications:
    • Temperature grade 1:
      –40°C to +125°C, TA
  • Integrated MOSFET for buck, buck-boost and boost topology
    • Wide input voltage: 4.5 V to 65 V
    • Integrated 5.2-A and 150-mΩ MOSFET
    • Switching frequency 100 kHz to 2.2 MHz
    • Spread spectrum for lower EMI
  • High precision power FET dimming
    • Up to 4-A output current in buck topology
    • Analog dimming (dimming ratio 256 :1)
    • Fast PWM dimming (150-ns pulse width)
    • Hybrid and flexible dimming
  • Full protection features:
    • Fault output
    • LED open and short protection
    • Cycle-by-cycle current limit
    • Switching FET failure protection
    • Thermal shutdown
    • Configurable thermal foldback curve

2 Applications

  • Automotive infotainment
  • Automotive instrument clusters
  • Heads-up displays(HUD)
  • Automotive lighting
GUID-20231016-SS0I-J8H9-FVR6-CB0Q9V4SV0JX-low.svg Typical Boost LED Driver Application Schematic

3 Description

The LP8868-Q1 family is a non-synchronous multi-topology solution with 4.5-V to 65-V wide input range. By integrating the low-side NMOS switch, the device is capable of driving LEDs with high power density and high efficiency. The family also supports common cathode connection and single layer PCB design. The switching frequency is configurable from 100 kHz to 2.2 MHz with an optional spread spectrum feature for better EMI performance.

The LP8868-Q1 family supports four dimming options, including analog, PWM, hybrid and flexible dimming. Each dimming method can be configured through the PWM and ADIM input pins by means of simple high and low signals. The family adopts an adaptive off-time current mode control along with smart and accurate sampling to enable inductive fast dimming (IFD) and achieve high dimming accuracy.

The LP8868-Q1 family also provides multiple systematic protections, including LED open and short, sense resistor open and short, configurable thermal foldback and thermal shutdown. Fault output will send out acknowledge signals as soon as any fault condition is detected.

Package Information
PART NUMBERPACKAGE1BODY SIZE (NOM)
LP8868-Q1VSON (14)4.5 mm x 3.0 mm
HVSSOP (12)2 4 mm x 3.0 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.
  2. Product preview
GUID-20231029-SS0I-3D1Z-S92N-18TZPVXRWTTX-low.svg Efficiency VS Input Voltage

4 Comparison Table

Part Number Topology MOSFET Current Limit (Typical) Spread Spectrum
LP8868XQDMTRQ1 Boost 6 A Enabled
LP8868YQDMTRQ1 Buck-boost 6 A Enabled
LP8868ZQDMTRQ1 Buck 6 A Enabled
LP8868UQDMTRQ1 Boost 6 A Disabled
LP8868VQDMTRQ1 Buck-boost 6 A Disabled
LP8868WQDMTRQ1 Buck 6 A Disabled

5 Pin Configuration and Functions

GUID-5140BF05-AD8E-4222-B3A2-663C140B68AA-low.gifFigure 5-1 14-Pin Buck VSONTop View
GUID-3F8DD51E-B08C-47E6-BFDA-E844F50D80B9-low.gif

HVSSOP is product preview

Figure 5-2 12-Pin Buck HVSSOPTop View
Table 5-1 Pin Functions
PIN TYPE(1) DESCRIPTION
No. NAME
1 PGND G Power ground pin.
2 AGND G Analog ground pin.
3 VIN P Input power pin.
4 VCC P Internal LDO output pin. Connect with a 10-V, 1-uF capacitor to GND.
5 ADIM/HD I Analog dimming or hybrid dimming pin. Pull high for PWM dimming only, pull low for hybrid dimming, input PWM signal for analog dimming.
6 PWM/EN I PWM dimming or EN pin. Pull high for always on, pull low for disabling the device, input PWM signal for PWM dimming.
7 FAULT O Open drain output. Pull low when fault is detected.
8 TEMP I/O Thermal foldback pin. Put different resistor values to GND to set different thermal foldback behavior curves.
9 FSET I/O Switching frequency set pin, with range of 100 kHz ~ 2.2 MHz. Put different resistor values to GND for different switching frequencies.
10 COMP I/O Error-amilifier output. Connect capacitors to GND. Different capacitor values determine different softstart times and bandwidths.
11 UVP I Undervoltage detection pin. Put different resistor dividers to set the LED open detection thresholds.
12 CSP I LED current sense positive pin.
13 CSN I LED current sense negative pin.
14 SW P Switching node pin. Internally connected to the low-side MOSFET. Connect with the power inductor and the schottky diode.
Pad Thermal Pad G Power ground pin.
GUID-58608632-3C10-495F-BA29-C213439B5BA9-low.gifFigure 5-3 14-Pin Boost/Buck-Boost VSONTop View
GUID-5140BF05-AD8E-4222-B3A2-663C140B68AA-low.gif

HVSSOP is product preview

Figure 5-4 12-Pin Boost/Buck-Boost HVSSOPTop View
Table 5-2 Pin Functions for boost/buck-boost topology
PIN TYPE(1) DESCRIPTION
VSON Package NAME
1 PGND G Power ground pin.
2 AGND G Analog ground pin.
3 VIN P Input power pin.
4 VCC P Internal LDO output pin. Connect with a 10-V, 1-uF capacitor to GND.
5 ADIM/HD I Analog dimming or hybrid dimming pin. Pull high for PWM dimming only, pull low for hybrid dimming, input PWM signal for analog dimming.
6 PWM/EN I PWM dimming or EN pin. Pull high for always on, pull low for disabling the device, input PWM signal for PWM dimming.
7 FAULT O Open drain output. Pull low when fault is detected.
8 TEMP I/O Thermal foldback pin. Put different resistor values to GND to set different thermal foldback behavior curves.
9 FSET I/O Switching frequency set pin, with range of 100 kHz ~ 2.2 MHz. Put different resistor values to GND for different switching frequencies.
10 COMP I/O Error-amilifier output. Connect capacitors to GND. Different capacitor values determine different softstart times and bandwidths.
11 OVP I Overvoltage detection pin. Put different resistor dividers to set the LED open detection thresholds.
12 CSN I LED current sense negative pin.
13 CSP I LED current sense positive pin.
14 SW P Switching node pin. Internally connected to the low-side MOSFET. Connect with the power inductor and the schottky diode.
Pad Thermal Pad G Power ground pin.
(1) I = Input, O = Output, P = Supply, G = Ground

 
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