SLVSBD1B December 2012 – August 2025 TPS65175
PRODUCTION DATA
- 1
- 1 Features
- 2 Applications
- 3 Description
- 4 Pin Configurations
- 5 Ordering Information #GUID-A66BA10C-7D19-4133-842F-4CC0C2AD52C6/SLVSAP8211
- 6 Specifications
- 7 DAC Range Summary
-
8 Detailed Description
- 8.1 Boost Converter (VDD)
- 8.2 Boost Converter Design Procedure
- 8.3 Buck Converter (VCC)
- 8.4 Buck Converter Design Procedure
- 8.5 Synchronous Buck Converter (HVDD)
- 8.6 Synchronous Buck Converter Design Procedure
- 8.7 Positive Charge Pump Controller (VGH) and Temperature Compensation
- 8.8 Positive Charge Pump Design Procedure
- 8.9 VGH Temperature Compensation
- 8.10 Negative Charge Pump (VGL)
- 8.11 Negative Charge Pump Design Procedure
- 8.12 P-Vcom Voltage and Gain (VCOM)
- 8.13 P-Vcom Design Procedure
- 8.14 P-Vcom Temperature Compensation
- 8.15 Gamma Buffer (GMA1-GMA6)
- 8.16 Level Shifters
- 8.17 State Machine
- 8.18 GCLK
- 8.19 MCLK
- 8.20 GST
- 8.21 E/O
- 8.22 Reverse
- 8.23 VGH_F and VGH_R
- 8.24 VST
- 8.25 RESET
- 8.26 EVEN and ODD
- 8.27 Abnormal Operation
- 8.28 CLK1 to CLK6
- 8.29 Gate Voltage Shaping
- 8.30 Power Supply Sequencing (CLK1-CLK6, VST, RESET)
- 8.31 Power Supply Sequencing (EVEN, ODD)
- 8.32 Power Supply Sequencing (VGH_F, VGH_R)
- 101
- 8.33 Typical Applications
- 9 APPENDIX – I2C INTERFACE
- 10Detailed Description
- 11Register Map
- 12DAC Registers
- 13Electrostatic Discharge Caution
- 14Revision History
- 15Mechanical, Packaging, and Orderable Information
8.11.3 Selecting the NPN Transistor (CPN)
The NPN transistor used to regulate VGL should have a DC gain (hFE) of at least 100 when its collector current is equal to the charge pump's output current. The transistor should also be able to withstand voltages up to VIN across its collector-emitter (VCE).
The transistor must be able to dissipate this power without its junction becoming too hot. Note that the ability to dissipate power depends heavily on adequate PCB thermal design. The power dissipated in the transistor is given by the following equation:
IGL = Mean output current on VGL
VF = Diode forward voltage
A pull-down resistor is also required between the transistor's base and emitter. The value of this resistor is not critical, but it should be large enough not to divert significant current away from the base of the transistor. A value of 100 kΩ is suitable for most applications