Light-emitting element driving circuit and light-emitting element driving chip

1 . A light-emitting element driving circuit, comprising a driving power supply stage and an impedance-adjustable module arranged on a branch where a light-emitting element is located, and an impedance adjusting branch connected in parallel with the driving power supply stage, wherein an adjustment output terminal of the impedance adjusting branch is coupled to the impedance adjustable module; and

the impedance adjusting branch is configured to adjust an impedance of the impedance-adjustable module according to voltages on both sides of the driving power supply stage.

2 . The light-emitting element driving circuit according to claim 1 , wherein the impedance adjusting branch is configured to: in response to a voltage drop at the driving power supply stage being greater than a predetermined compensation voltage value, adjust the impedance of the impedance-adjustable module to increase; and/or the impedance adjusting branch is configured to: in response to the voltage drop at the driving power supply stage being less than a predetermined compensation voltage value, adjust the impedance of the impedance-adjustable module to decrease.

3 . The light-emitting element driving circuit according to claim 2 , wherein the voltage drop at the driving power supply stage is a difference between a voltage value of a driving input terminal of the driving power supply stage and a voltage value of a driving output terminal of the driving power supply stage;

the impedance adjusting branch is configured to: in response to the voltage drop at the driving power supply stage being greater than a predetermined compensation voltage value, adjust the impedance of the impedance-adjustable module to increase continuously until the difference between the voltage value of the driving input terminal and the voltage value of the driving output terminal approximates to the compensation voltage value; and

the impedance adjusting branch is configured to: in response to the voltage drop at the driving power supply stage being less than a predetermined compensation voltage value, adjust the impedance of the impedance-adjustable module to decrease continuously until the difference between the voltage value of the driving input terminal and the voltage value of the driving output terminal approximates to the compensation voltage value.

4 . The light-emitting element driving circuit according to claim 1 , wherein the impedance-adjustable module comprises a shunting module and a variable resistance module that are connected in parallel with each other.

5 . The light-emitting element driving circuit according to claim 4 , wherein the adjustment output terminal is coupled to an adjustment control terminal of the variable resistance module; and the impedance adjusting branch is configured to adjust an impedance of the variable resistance module according to the voltages on both sides of the driving power supply stage.

6 . The light-emitting element driving circuit according to claim 5 , wherein the impedance adjusting branch is configured to: in response to the voltage drop at the driving power supply stage being greater than a predetermined compensation voltage value, adjust an impedance of the variable resistance module to increase; and/or the impedance adjusting branch is configured to: in response to the voltage drop at the driving power supply stage being less than a predetermined compensation voltage value, adjust the impedance of the variable resistance module to decrease.

7 . The light-emitting element driving circuit according to claim 1 , wherein the impedance adjusting branch comprises a compensation circuit and an error amplification circuit; an output terminal of the error amplification circuit is coupled to the impedance-adjustable module; a first input terminal of the error amplification circuit is coupled between the driving power supply stage and the light-emitting element through the compensation circuit, and a second input terminal of the error amplification circuit is coupled to the other terminal of the driving power supply stage that is not coupled with the light-emitting element; and the compensation circuit is configured to compensate a compensation voltage of the driving power supply stage.

8 . The light-emitting element driving circuit according to claim 7 , further comprising a sampling circuit, wherein the error amplification circuit is coupled to a point between the driving power supply stage and the light-emitting element through the compensation circuit and the sampling circuit; the sampling circuit is configured to collect an extremum voltage values at a node between the driving power supply stage and the light-emitting element; and the compensation circuit is configured to compensate the extremum voltage values according to the compensation voltage.

9 . The light-emitting element driving circuit according to claim 8 , wherein when the light-emitting element is coupled to the driving input terminal of the driving power supply stage, the sampling circuit is configured to collect a sampling voltage with a minimum voltage value at the driving input terminal; the compensation circuit is configured to negatively compensate the sampling voltage according to the compensation voltage; and

when the light-emitting element is coupled to the driving output terminal of the driving power supply stage, the sampling circuit is configured to collect a sampling voltage with a maximum voltage value at the driving output terminal; and the compensation circuit is configured to positively compensate the sampling voltage according to the compensation voltage.

10 . The light-emitting element driving circuit according to claim 8 , wherein the impedance-adjustable module is connected between a power supply and a driving input terminal of the driving power supply stage, and the light-emitting element is connected between a driving output terminal of the driving power supply stage and ground; the compensation circuit comprises a first N-type transistor, a first P-type transistor and a compensation resistor; and

a gate of the first N-type transistor is coupled to the sampling circuit, a drain of the first N-type transistor is coupled to the power supply, and a source of the first N-type transistor is coupled to a gate of the first P-type transistor; and a drain of the first P-type transistor is grounded, and a source of the first P-type transistor is coupled to the error amplification circuit through the compensation resistor.

11 . The light-emitting element driving circuit according to claim 8 , wherein the impedance-adjustable module is connected between the driving output terminal of the driving power supply stage and the ground, and the light-emitting element is connected between the power supply and the driving input terminal of the driving power supply stage; the compensation circuit comprises a first P-type transistor, a first N-type transistor and a compensation resistor; and

a gate of the first P-type transistor is coupled to the sampling circuit, a drain of the first P-type transistor is grounded, and a source of the first P-type transistor is coupled to a gate of the first N-type transistor; and a drain of the first N-type transistor is coupled to a power supply, and a source of the first N-type transistor is coupled to the error amplification circuit through the compensation resistor.

12 . The light-emitting element driving circuit according to claim 8 , wherein the sampling circuit comprises an output transistor, a first input transistor, a second input transistor, a first mirror branch and a second mirror branch; the first input transistor and the second input transistor are connected in parallel with each other and are connected to the first mirror branch, and the output transistor is connected to the second mirror branch; and

a control terminal of the first input transistor is connected to a first driving branch of the driving power supply stage, and a control terminal of the second input transistor is connected to a second driving branch of the driving power supply stage.

13 . The light-emitting element driving circuit according to claim 1 , wherein a plurality of light-emitting elements is provided to form at least a first light-emitting branch and a second light-emitting branch which are connected in parallel with each other; the driving power supply stage comprises at least a first driving branch and a second driving branch; the first light-emitting branch is coupled to the first driving branch to form a first channel, and the second light-emitting branch is coupled to the second driving branch to form a second channel; and the first channel and the second channel are connected in parallel.

14 . The light-emitting element driving circuit according to claim 13 , further comprising a current control circuit and a configuration resistor, wherein a control output terminal of the current control circuit is connected to the first driving branch and the second driving branch, and the configuration resistor is connected between a configuration input terminal of the current control circuit and ground.

15 . A light-emitting element driving chip, comprising the light-emitting element driving circuit according to claim 1 , wherein the impedance-adjustable module comprises a shunting module and a variable resistance module; the light-emitting element driving chip further comprises a substrate; the variable resistance module, the driving power supply stage and the impedance adjusting branch are arranged on the substrate; the shunting module is arranged outside the substrate; the variable resistance module comprises one or more of a variable resistor and an adjusting transistor; and the shunting module comprises a shunting resistor.