CN206341450U - Great power LED constant-current driven chip - Google Patents

Abstract

Great power LED constant-current driven chip.Traditional die typical case's application scheme input voltage amplitude of variation is no more than ± 10%, if it exceeds the scope, output current trueness error will be dramatically increased.The utility model composition includes logic control circuit（1）, logic control circuit respectively with ON time control circuit（2）, minimum turn-off time circuit（3）, under-voltage protecting circuit（4）, TSD overheating protection circuits（5）, level shifting circuit（6）, current limliting timer connection（7）, level shifting circuit and raster data model under-voltage protecting circuit（8）Connection, current limliting timer detects circuit with BUCK switching currents（9）Connection, raster data model under-voltage protecting circuit and voltage regulator high pressure LDO（10）Connection, BUCK switching currents detection circuit is connected with level shifting circuit, raster data model under-voltage protecting circuit, voltage regulator high pressure LDO respectively.The utility model is applied to great power LED constant-current driven chip.

Description

Great power LED constant-current driven chip

Technical field：

The utility model is related to a kind of great power LED constant-current driven chip.

Background technology：

LED is by energy resource consumption is low, luminous efficiency is high, environmentally friendly, long service life, numerous advantages such as safe and reliable are in illumination Field obtains one seat, and has the trend constantly expanded, and same LED Lighting Industries also bring very significant economic effect Benefit and social benefit.Therefore, the rapid popularization of LED illumination has also driven flourishing for LED drive chip industry so that LED Driving chip turns into the important component in electric power management circuit market.Due to the brightness and its conducting electric current of LED illumination Intensity it is closely related, constant current driving be optimal selection.And the typical application scheme of traditional chip becomes to input voltage Change amplitude requirement higher, be usually no more than ± 10%, if input voltage amplitude of variation exceedes this scope, output current precision Error will be dramatically increased, so designing a kind of new constant current driver circuit for LED on the basis of traditional die.

Utility model content：

The purpose of this utility model is to provide a kind of great power LED constant-current driven chip.

Above-mentioned purpose is realized by following technical scheme：

A kind of great power LED constant-current driven chip, its composition includes：Logic control circuit, described logic control circuit Respectively with ON time control circuit, minimum turn-off time circuit, under-voltage protecting circuit, TSD overheating protection circuits, level conversion Circuit, the connection of current limliting timer, described level shifting circuit are connected with raster data model under-voltage protecting circuit, and described current limliting is determined When device and BUCK switching currents detection circuit be connected, described raster data model under-voltage protecting circuit and voltage regulator high pressure LDO Connection, described BUCK switching currents detection circuit respectively with described level shifting circuit, described raster data model is under-voltage protects Protection circuit, described voltage regulator high pressure LDO connections.

The beneficial effects of the utility model：

1. the utility model is DC/DC voltage-dropping type LED constant current driving chips, its wide input voltage range reaches 6 V to 45 V, output forward current reaches as high as 1.5 A, can meet most of DC application, can make to flow through no more than maximum output voltage Series LED electric current it is stable.Using sluggish control model, using the not mutability of inductive current in Buck circuits, pass through The feedback voltage of sampling resistor and the reference voltage of chip internal are compared, and output voltage is controlled by internal switch mosfet Conducting is closed, so as to realize the purpose of constant current, constant current driving is carried out to LED.This chip has that reference voltage is low, transient state is rung simultaneously Should be exceedingly fast, digital (PWM) light modulation, UVLO under-voltage protections, overtemperature protection the characteristics of.Control of this chip based on control ON time Mode realizes high accuracy, and has the functions such as wide input voltage range, low reference voltage source and PWM light modulations, and driving current can 1.5 A are reached, and just being capable of steady operation without compensation.

In Fig. 2, R1 and R2 resistance with the addition of respectively in VIN ports and Vjb ports, wherein R1 is big resistance, designs resistance Larger, R2 is small resistor, and design resistance is smaller.When input voltage VIN increase, feedback voltage V CS2 is consequently increased, and this will rise Counteracting output current increases and increased effect with input voltage, as long as so big resistance R1 and small resistor R2 chooses properly, The relation of output current IF and input voltage VIN can be seen that just by the mathematical relationship between the R1 on R2 and denominator on molecule Become very little, it might even be possible to ignore.Chip typical case's application is solved using LED drive schemes of the present utility model The problem of drive circuit input voltage amplitude of variation can only be limited in ± 10%, allows input voltage amplitude of variation to reach ± 50% It is even more many, the function of the chip is significantly improved, the chip application scope has further been widened.

Brief description of the drawings：

Accompanying drawing 1 is circuit theory diagrams of the present utility model.

Accompanying drawing 2 is the circuit theory diagrams that LED is driven using this great power LED constant-current driven chip.

Embodiment：

Embodiment 1：

A kind of great power LED constant-current driven chip, its composition includes：Logic control circuit 1, described logic control circuit Respectively with ON time control circuit 2, minimum turn-off time circuit 3, under-voltage protecting circuit 4, TSD overheating protection circuits 5, level Change-over circuit 6, current limliting timer 7 are connected, and described level shifting circuit is connected with raster data model under-voltage protecting circuit 8, described Current limliting timer and BUCK switching currents detection circuit 9 be connected, described raster data model under-voltage protecting circuit and voltage-regulation Device high pressure LDO, piece number：10 connections, described BUCK switching currents detection circuit respectively with described level shifting circuit, described Raster data model under-voltage protecting circuit, described voltage regulator high pressure LDO connections.

Embodiment 2：

Great power LED constant-current driven chip according to embodiment 1, after input voltage VIN is connected, voltage regulator High pressure LDO is started working, and 5 V power supply VOUT is provided for analog control circuit part.When under-voltage latch units (UVLO) monitoring , can be to biasing circuit module, overheating protection circuit module, logic control circuit modules and driving when reaching 4 V to LDO output Circuit module sends enable signal (EN), and now chip whole system is started working, built-in NLDMOS power devices M1 conductings, electricity Sense L electric current is begun to ramp up, and because the electric current on sampling resistor RSNS is equal to the electric current on inductance L, the electric current flows through feedback electricity Hinder after RSNS, chip internal can be fed back to by Vfb pins by producing feedback voltage V a SNS, VSNS, and can be produced in Vfb pins The reference voltage Vref (design chips are 200 mV) that life one is produced by chip internal benchmark, now the comparator meeting in chip Feedback voltage V SNS and reference voltage Vref are compared, if feedback voltage V SNS is less than reference voltage Vref, then core Sector-meeting makes the NLDMOS conductings of inside, and the time TON of conducting is resistance RON and input voltage VIN institute by being connected with clt pins Determine.After ON time TON terminates, NLDMOS can turn off a time, and this time is referred to as the minimum turn-off time TOFF-MIN (the chip minimum turn-off time of design is 200 ns).After minimum turn-off time TOFF-MIN terminates, chip pair VSNS and reference voltage Vref are compared, if VSNS is less than Vref, M1 conductings start circulation work next time, again Compare the size between feedback voltage V SNS and reference voltage Vref.In addition, when NLDMOS is turned on, if outer member such as electricity The value for hindering RON and inductance L is incorrect, and such as resistance RON is excessive or inductance L is too small, so as to cause the voltage drop on Vfb to surpass 300 mV are crossed, being now connected to the output state signal of another comparator at Vfb ends can overturn, force NLDMOS shut-offs, Chip is stopped.

This chip has 8 pins, and important pin has input pin VIN, switch pin SW, power NLDMOS drive module Floating power supply pin VCC and grounding leg VSS.An electric capacity is connected between supply pin VCC and switch pin SW in chip application, Therefore, supply pin VCC pad is disposed close to switch pin SW place.In addition chip circumference is all ground wire, to ground connection The design that pin VSS pads are placed is mainly in view of grounding leg VSS is needed close to Voltage Reference source module, and other pin pads are put Put and mainly consider from chip area is saved.

Claims (1)

1. a kind of great power LED constant-current driven chip, its composition includes：Logic control circuit, it is characterized in that：Described logic control Circuit processed controls circuit, minimum turn-off time circuit, under-voltage protecting circuit, TSD overheating protection circuits, electricity with ON time respectively Flat change-over circuit, the connection of current limliting timer, described level shifting circuit is connected with raster data model under-voltage protecting circuit, described Current limliting timer is connected with BUCK switching currents detection circuit, and described raster data model under-voltage protecting circuit and voltage regulator is high LDO connections are pressed, described BUCK switching currents detection circuit is owed with described level shifting circuit, described raster data model respectively Voltage protection circuit, described voltage regulator high pressure LDO connections.