CN112398326A

CN112398326A - Soft start device and method based on multi-output device, power supply and chip

Info

Publication number: CN112398326A
Application number: CN201910746199.5A
Authority: CN
Inventors: 苏建华; 赵辉; 张存才; 冯立松
Original assignee: Nationz Technologies Inc
Current assignee: Nationz Technologies Inc
Priority date: 2019-08-13
Filing date: 2019-08-13
Publication date: 2021-02-23
Anticipated expiration: 2039-08-13
Also published as: CN112398326B

Abstract

The application relates to a soft start device based on a plurality of output devices, including: a first output device; the output end of the second output device is electrically connected with the output end of the first output device; and the driving unit is electrically connected with the control end of the first output device and the control end of the second output device, and controls the first output device to start power output at the power-on moment and controls the second output device to delay the start of power output at the power-on moment.

Description

Soft start device and method based on multi-output device, power supply and chip

Technical Field

The application belongs to the field of soft start circuits, and particularly relates to a soft start device, a soft start method, a soft start power supply device and a soft start chip based on multiple output devices.

Background

Low Drop-out (LDO) is one type of linear Regulator that is used to provide a stable DC voltage supply. The LDO has a very wide application range, can be independently manufactured into a chip, and can also be integrated in the chip to be used as an on-chip power supply module to provide a stable direct current power supply for the chip. To the off-chip Power supply of LDO, present many application batteries Power supply to satisfy the application of portable equipment, in addition for the Power saving, generally can let the chip enter into and fall the Power Down mode when not working, need the during operation to awaken the chip again. However, each time the chip is awakened, the chip is restarted, current is drawn from the battery to start the chip and charge the load capacitor, and if the surge (Inrush) current is too large, latch-up may be caused, and the electric quantity and the service life of the battery may be affected.

At present, soft start devices are generally used to attenuate inrush currents. The existing soft start circuit is generally arranged at a control end of an output device, and the power rising speed of the output device is controlled by limiting the rising speed of a driving signal of the control end alone, so that the surge current is weakened. The inventor finds that the surge current suppression effect of the method is limited, and the increasing system power requirement and the surge current amplitude control requirement are difficult to be considered at the same time.

Disclosure of Invention

One embodiment of the present application provides a soft-start apparatus based on a plurality of output devices, including: a first output device; a second output device, an output end of which is electrically connected with an output end of the first output device; and the driving unit is electrically connected with the control end of the first output device and the control end of the second output device, controls the first output device to start power output at the power-on moment, and controls the second output device to delay the start of power output at the power-on moment.

An embodiment of the present application further provides a soft start method based on multiple output devices, which is applied to any one of the soft start apparatuses described above, and includes: controlling the first output device to start power output at the power-on moment; and controlling the second output device to delay starting power output at the power-on moment.

An embodiment of the present application further provides a soft-start power supply apparatus based on multiple output devices, including any one of the soft-start apparatuses described above.

An embodiment of the present application further provides a soft-start chip based on multiple output devices, including any one of the soft-start apparatuses described above.

An embodiment of the present application further provides a power supply chip including any one of the foregoing power supply devices.

The soft start device, the soft start method, the soft start power supply device, the soft start chip and the soft start power supply chip are utilized. At least two output devices are arranged, and after the power-on moment is started, the power output of the output devices is started one by one.

At the moment of power-on, only the power output of the first output device is started, and the power output capability is low due to the fact that the output impedance of the single first output device is relatively high. The inrush current generated by the power output of the first output device is relatively low and is easier to control.

After the first output device outputs power for a period of time, the output capacitor is charged, and the voltage of the output capacitor gradually rises. And when the difference between the voltage of the capacitor and the target output voltage is reduced to a certain degree, controlling the second output device to start power output. Therefore, the power output capability is improved, the output impedance is reduced, and meanwhile, excessive surge current cannot be generated.

By utilizing the soft start device, the soft start method, the soft start power supply device, the soft start chip and the soft start power supply chip, the power output requirement of a system can be effectively considered, and the surge current during starting can be reduced.

Drawings

Fig. 1 is a schematic diagram of a soft-start apparatus based on a plurality of output devices according to an embodiment of the present application.

Fig. 2 is a schematic diagram of a soft-start apparatus based on a plurality of output devices according to an embodiment of the present application.

Fig. 3 is a schematic diagram of a soft-start apparatus based on a plurality of output devices according to an embodiment of the present application.

Fig. 4 is a schematic diagram of a soft-start apparatus based on a plurality of output devices according to an embodiment of the present application.

Fig. 4A is a waveform diagram illustrating a first delay voltage setup signal in the soft start apparatus shown in fig. 4.

Fig. 5 is a flowchart illustrating a soft-start method based on a plurality of output devices according to an embodiment of the present application.

Fig. 6 is a flowchart illustrating a soft-start method based on a plurality of output devices according to an embodiment of the present application.

Fig. 7 is a flowchart illustrating a soft-start method based on a plurality of output devices according to an embodiment of the present application.

Fig. 8 is a flowchart illustrating a soft-start method based on a plurality of output devices according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be understood that the terms "first," "second," "third," and "fourth," etc. in the claims, description, and drawings of the present application are used for distinguishing between different objects and not for describing a particular order. The terms "comprises" and "comprising," when used in the specification and claims of this application, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the present application herein is for the purpose of describing particular embodiments only, and is not intended to be limiting of the application. As used in the specification and claims of this application, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be further understood that the term "and/or" as used in the specification and claims of this application refers to any and all possible combinations of one or more of the associated listed items and includes such combinations.

Fig. 1 is a schematic diagram of a soft-start apparatus based on a plurality of output devices according to an embodiment of the present application. As shown in fig. 1: the soft start apparatus 1000 includes: a first output device Q1, a second output device Q2 and a driving unit P1. Wherein:

the output terminal of the second output device Q2 is electrically connected to the output terminal of the first output device Q1.

The driving unit P1 is electrically connected to a control terminal of the first output device Q1 and to a control terminal of the second output device Q2. The driving unit P1 controls the first output device Q1 to start power output at the power-on moment; and controls the second output device Q2 to delay enabling power output at the time of power-up.

As shown in fig. 1, Vin is an input power source and is electrically connected to power input terminals of the first output device Q1 and the second output device Q2.

As shown in fig. 1, C1 is the output capacitor of the soft-start device 1000, and is connected in parallel to the output terminal Vout of the soft-start device 1000.

As shown in fig. 1, the soft-start apparatus optionally includes an output terminal Vout electrically connected to an output terminal of the first output device Q1. Further, the output terminal Vout may also be electrically connected to the output terminal of the first output device Q1 through an inductor.

As shown in fig. 1, the first output device Q1 and the second output device Q2 are N-type field effect transistors. The control ends of the Q1 and the Q2 are grid (G) poles, the power input end is a source (S) pole, and the output end is a drain (D) pole. Alternatively, Q1 and Q2 may adopt other connection modes.

As shown in fig. 1, the first output device Q1 and the second output device Q2 may alternatively be P-type fets. Further, the first output device Q1 and the second output device Q2 may also be other types of unipolar transistors. Still further the first output device Q1 and the second output device Q2 may also be bipolar transistors.

Alternatively, the power-on time may be a voltage establishment time of the input power Vin, a time when the driving unit P1 receives an enable instruction, or a time when an input signal provided by a signal source (not shown) is established.

Alternatively, when the first output device Q1 and the second output device Q2 both start power output, the receiving driving signals of the two devices may be the same or different.

Optionally, the soft start apparatus 1000 may further include: an nth output device QN (not shown), where N is an integer greater than 2. The output ends of the output devices Q1-QN are electrically connected with each other; the control terminals of the output devices Q1-QN are electrically connected to the driving unit P1, respectively. At the power-on time, the driving unit P1 controls the output devices Q1-QN to respectively start power output one by one.

Further, the driving unit P1 controls the output devices Q1-QN to enable power output one by one according to the voltage variation of the output terminal Vout, and also controls the output devices Q1-QN to enable power output one by one according to different predetermined delay times.

Fig. 2 is a schematic diagram of a soft-start apparatus based on a plurality of output devices according to an embodiment of the present application. As shown in fig. 2, the soft start apparatus 2000 includes: a first output device Q1, a second output device Q2, an output terminal Vout, and a driving unit P1.

The first output device Q1, the second output device Q2, and the output terminal Vout are the same as the devices with the same name in the soft start apparatus 1000, and are not described in detail.

The drive unit P1 includes: switch K1, first controller U1, power-on reset U2. Wherein:

the first controller U1 is connected to the control terminal of the first output device Q1, and controls the first output device Q1 to enable power output at the power-on time.

The switch K1 is a double-throw switch, and the fixed end of the switch K1 is electrically connected with the control end of the second output device Q2; two contacts of the switch K1 are electrically connected with the first controller U1 and the input power source Vin, respectively. When the K1 is conductively connected with the input power Vin, the second output device Q2 stops power output; when the K1 is conductively connected to the first controller U1, the second output device Q2 is controlled by the first controller U1 to enable power output.

The power-on reset device U2 is electrically connected to the output terminal Vout of the soft start device 2000 and to the control terminal of the switch K1. The power-on reset U2 detects whether the output terminal Vout of the soft-start device 2000 exceeds a first threshold Vth 1; if yes, controlling a second output device Q2 to start power output through a switch K1; if not, the second output device Q2 is controlled to stop power output through the switch K1.

As shown in fig. 2, at the time of power-up, the power-on reset U2 controls K1 to conduct with Vin, and at this time, the second output device Q2 has no power output. The first controller U1 drives the first output device Q1 to start power output, and the voltage at the output terminal Vout of the soft start device 2000 is gradually increased. When the power-on reset device U2 detects that the voltage at the output terminal Vout exceeds the first threshold Vth1, the power-on reset device U2 controls the switch K1 to conduct with the first controller U1. The second output device Q2 is driven and controlled by the first controller U1 to output power to the output terminal Vout.

As shown in fig. 2, the first controller U1 may be a linear voltage output or a Pulse Width Modulated (PWM) output.

As shown in fig. 2, the switch K1 may also be connected to a separate controller U6 (not shown) instead of the first controller U1. When the second output device Q2 needs to be controlled to start power output, the switch K1 is connected to the controller U6, and the controller U6 drives the second output device Q2 to output power to the output terminal Vout. The independent controller may be a linear voltage output or a Pulse Width Modulated (PWM) output.

As shown in fig. 2, the switch K1 can alternatively be replaced by two separate switches K2 (not shown) and K3 (not shown) with opposite control logics. One end of the switch K2 is connected to the control end of the second output device Q2, and the other end is connected to the first controller U1; one end of the switch K3 is connected to the control end of the second output device Q2, and the other end is connected to the input power Vin. When the switch K2 is opened and the switch K3 is closed, the output device Q2 stops power output; when the switch K2 is closed and the switch K3 is opened, the output device Q2 is driven and controlled by the control U1 to start power output.

Further, the switch K1 may also be a single-pole single-throw switch (not shown), and two power terminals are respectively connected to the first controller U1 and the control terminal of the output device Q2. A resistor (not shown) is connected across the control terminal of the output device Q2 and the input supply Vin. When the switch K1 is open, the output device Q2 stops power output; when K1 is turned on, the output device Q2 is subjected to drive control by the first controller U1, and power output is started.

Alternatively, the switch K1 may be replaced by other local circuits that can control the start/stop of power output by the output device Q2.

Fig. 3 is a schematic diagram of a soft-start apparatus based on a plurality of output devices according to an embodiment of the present application. As shown in fig. 3, the soft start apparatus 3000 includes: a first output device Q1, a second output device Q2, an output terminal Vout, and a driving unit P1. Wherein P1 includes: the controller comprises a first controller U1, a time delay unit U3 and a switch K1. Wherein:

the first output device Q1, the second output device Q2, the output terminal Vout, the first controller U1, and the switch K1 are the same as the devices with the same name in the soft-start apparatus 2000, and are not described in detail.

And the delay unit U3 is electrically connected with the control end of the switch K1. At the power-on moment, the delay unit U3 controls the second output device Q2 to stop power output through the switch K1; after a predetermined delay time after the power-on time, the second output device Q2 is controlled to start power output through the switch K1.

As shown in fig. 3, the delay unit U3 may optionally include a resistance-capacitance circuit, a capacitance-sensing circuit, or other local circuits that may produce a delay effect.

Fig. 4 is a schematic diagram of a soft-start apparatus based on a plurality of output devices according to an embodiment of the present application. As shown in fig. 4, the soft start apparatus 4000 includes: a first output device Q1, a second output device Q2, an output terminal Vout, and a driving unit P1. Wherein P1 includes: a first amplifying circuit U4, a first delay voltage establishing circuit U5, and a second controller U6. Wherein:

The second controller U6 is electrically connected to the control terminal of the second output device Q2. At power-up time, the second output device Q2 is controlled to delay enabling power output.

The first delayed voltage set-up circuit U5 receives the power-up signal S1 and generates the first delayed voltage set-up signal SSA according to the power-up signal S1.

An output end of the first amplifying circuit U4 is electrically connected to a control end of the first output device Q1, a signal input end of the first amplifying circuit U4 is electrically connected to the first delay voltage establishing circuit U5, and a feedback input end of the first amplifying circuit U4 is electrically connected to an output end Vout of the soft start device 4000. The first amplifying circuit U4 generates a first driving signal (not shown) according to the first delay voltage establishment signal SSA, and controls the output power of the first output device to slowly increase by using the first driving signal.

The first delayed voltage setting circuit U5 generates the first delayed voltage setting signal SSA having a relatively long voltage setting time, instead of the influence of the power-up signal S1 on the subsequent circuit, according to the power-up signal S1. As shown in fig. 4A, when the upper electrical signal S1 is a step signal, the voltage establishment process of the first delayed-voltage establishment signal SSA may be a relatively slow, ramp-like process.

As shown in fig. 4, the first delay voltage establishing circuit U5 may include: the method comprises the following steps: a resistance-capacitance delay voltage build-up circuit (not shown), a capacitance-inductance delay voltage build-up circuit (not shown), or a resistance-inductance delay voltage build-up circuit (not shown).

As shown in fig. 4, S1 may be an input signal (not shown) from a signal source (not shown), or may be a result of an operation of the input signal from the signal source and an enable signal (not shown). S1 may also be the result of an input signal from a signal source, an enable signal, and the voltage of the input power Vin.

As shown in fig. 4, the first driving signal is a signal generated according to the first delay voltage establishment signal SSA and may be directly used to drive the first output device Q1. The first driving signal may be a linear voltage signal, a pulse width modulation signal, or any other signal directly used to control the first output device Q1.

As shown in fig. 4, the first driving signal may be synchronous with the first delayed voltage setup signal SSA or may lag behind the first delayed voltage setup signal SSA. Accordingly, the first amplifying circuit U4 may further include: the hysteresis circuit causes the first driving signal to lag behind the first delay voltage establishment signal SSA.

As shown in fig. 4, the second controller U6 may optionally include a switch K1 and a power-on reset U2 in the soft start device 2000. Or alternatively, the second controller U6 may also include the switch K1 and/or the delay unit U3 in the soft start apparatus 3000.

Further, the second controller U6 may further include a circuit device similar to the first delay voltage establishing circuit U5, and controls the output power of the second output device Q2 to slowly increase at the time of starting.

Fig. 5 is a flowchart illustrating a soft-start method based on a plurality of output devices according to an embodiment of the present application. As shown in fig. 5, the method 5000 is applied to any one of the soft start circuits, including step S510 and step S520. Wherein:

in step S510, at the time of power-on, the first output device Q1 is controlled to start power output.

In step S520, at the power-on time, the second output device Q2 is controlled to delay the start of power output.

At the power-on moment, the first output device Q1 is controlled to start power output, the first output device Q1 charges the output capacitor C1 with relatively small power output capacity and relatively large output impedance, so that the amplitude of surge current is controlled, and damage of the surge current to a circuit is reduced. When the voltage Vout at the output terminal rises to a certain level, the output capacitor C1 is charged, and the voltage at the two terminals of the capacitor C1 decreases to a certain level by the difference expected from the output of the soft start circuit, and then the second output device Q2 is controlled to start power output. The power output of the second output device Q2 does not cause a large inrush current while improving the power output capability and reducing the output impedance.

Optionally, the power-on time may be a voltage establishment time of the input voltage Vin, a time when the driving unit P1 receives an enable instruction, or a time when a voltage establishment of an input signal from a signal source is performed.

Optionally, the method 1000 may further include:

and controlling an Nth output device to delay starting power output, wherein N is an integer greater than 2. Optionally, the power output start timing of the nth output device lags the power output start timing of the N-1 th output device.

Fig. 6 is a flowchart illustrating a soft-start method based on a plurality of output devices according to an embodiment of the present application. As shown in fig. 6, the method 6000 includes: step S610, step S620, step S630, step S640, and step S650. Wherein the content of the first and second substances,

step S610 is the same as step S510 in the method 5000, and is not described herein again.

In step S620, the second output device Q2 is controlled to stop power output.

Step S630, the output terminal voltage Vout is collected.

Step S640, determining whether the output end voltage Vout is greater than a first threshold Vth 1; if yes, go to step S650; if not, the process proceeds to step S620.

In step S650, the second output device Q2 is controlled to start power output.

Alternatively, step S620 may be provided before step S610.

Optionally, the method 6000 may further include: and judging whether the voltage Vout of the output end is larger than the N-1 threshold, if so, controlling the Nth output device QN to start power output. Wherein the N-1 th threshold is larger than the N-2 th threshold, and N is an integer larger than 2.

Fig. 7 is a flowchart of a soft-start method 7000 based on a plurality of output devices according to an embodiment of the present application. As shown in fig. 7, method 7000 includes: step S710, step S720, and step S740. Wherein the content of the first and second substances,

in step S710, the first output device Q1 starts power output.

And step S720, controlling the second output device to stop power output.

In step S740, after delaying the preset first delay time, the second output device Q2 is controlled to start power output.

Alternatively, step S720 may be provided before step S710.

Optionally, method 7000 may further comprise: and after delaying the preset N-1 th delay time, controlling an Nth output device QN to start power output, wherein N is an integer larger than 2, and the Nth delay time is larger than the N-1 th delay time.

Fig. 8 is a flowchart illustrating a soft-start method based on a plurality of output devices according to an embodiment of the present application. As shown in fig. 8, method 8000 includes: step S810, step S820, step S830, and step S840. Wherein the content of the first and second substances,

in step S810, a first voltage establishment signal SSA is generated according to the power-on signal S1.

In step S820, a first driving signal is generated according to the first voltage establishment signal SSA.

In step S830, the output power of the first output device Q1 is controlled to slowly increase according to the first driving signal.

In step S840, the second output device Q2 is controlled to delay enabling power output.

As shown in fig. 8, the signal SSA in step S810 is a signal lagging behind the power-on signal S1. For example, when the upper electrical signal is a step signal, the signal waveform of the SSA is as shown in fig. 4A.

As shown in fig. 8, the first driving signal is a control signal generated based on the first voltage setup signal SSA, which can be directly used to drive the first output device. Alternatively, the first driving signal may be a linear voltage signal, or may be a pulse width modulation signal.

Alternatively, the first driving signal may be synchronized with the first voltage setup signal SSA or may lag behind the first voltage setup signal SSA.

The output power of the first output device Q1 controlled by the first drive signal rises slowly due to hysteresis of the first drive signal.

As shown in fig. 8, step S840 may optionally be the same as step S520 in method 5000. Or alternatively, step S840 may be replaced with steps S620-S650 of method 6000. Further, step S840 may be replaced with steps S720-S740 of method 7000.

As shown in fig. 8, step S840 may optionally further include a process similar to steps S810-S830, and the output power of the second output device Q2 is controlled to slowly rise when it is started.

As shown in fig. 8, further, the method 8000 may further include: and when the Nth output device is started, controlling the output power of the Nth output device to slowly rise.

The application also provides a soft start power supply device based on a plurality of output devices, which comprises any one of the soft start devices.

Optionally, the soft-start power supply apparatus may further include a signal source,

is connected with a driving unit in the soft starting device.

Alternatively, the power supply device may be a linear power supply or a switching power supply. Further, the power supply device may also be a low dropout regulator (LDO).

The application also provides a soft start chip based on a plurality of output devices, which comprises any one of the soft start devices.

The application also provides a soft start power supply chip based on a plurality of output devices, which comprises any one of the soft start power supplies.

Optionally, the first output device, the second output device and/or the signal source are disposed outside the power supply chip.

In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments. The technical features of the embodiments may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application, and the description of the embodiments is only intended to facilitate the understanding of the methods and their core concepts of the present application. Meanwhile, a person skilled in the art should, according to the idea of the present application, change or modify the embodiments and applications of the present application based on the scope of the present application. In view of the above, the description should not be taken as limiting the application.

Claims

1. A soft-start apparatus based on a plurality of output devices, comprising:

a first output device;

a second output device, an output end of which is electrically connected with an output end of the first output device;

and the driving unit is electrically connected with the control end of the first output device and the control end of the second output device, controls the first output device to start power output at the power-on moment, and controls the second output device to delay the start of power output at the power-on moment.

2. The soft start apparatus of claim 1, wherein the driving unit comprises:

and the first switch is electrically connected with the control end of the second output device and controls the second output device to start and/or stop power output.

3. The soft start apparatus of claim 2, further comprising:

the output end is electrically connected with the output end of the first output device or is connected with the output end of the first output device through an inductor;

wherein the driving unit further comprises:

and the power-on restorer is electrically connected with the output end of the soft starting device and the first switch, detects whether the voltage of the output end of the soft starting device exceeds a first threshold value, and controls the second output device to start power output through the first switch if the voltage of the output end of the soft starting device exceeds the first threshold value.

4. The soft-start apparatus of claim 2, wherein the drive unit further comprises:

and the time delay unit is electrically connected with the first switch and controls the second output device to start power output through the first switch after a preset first time delay time after the power-on moment.

5. The soft start apparatus of claim 1, wherein the drive unit further comprises:

the first delay voltage establishing circuit generates a first delay voltage establishing signal according to the electrifying signal;

and the first amplifier is electrically connected with the control end of the first output device and the first delay voltage establishing circuit, generates a first driving signal according to the first delay voltage establishing signal and controls the output power of the first output device to be slowly increased.

6. The soft-start apparatus of claim 5, wherein the first delayed-voltage establishing circuit comprises: the circuit comprises a resistance-capacitance delay voltage establishing circuit, a capacitance-inductance delay voltage establishing circuit or a resistance-inductance delay voltage establishing circuit.

7. A soft start method based on a plurality of output devices, applied to the soft start apparatus of any one of claims 1 to 6, comprising:

controlling the first output device to start power output at the power-on moment;

and controlling the second output device to delay starting power output at the power-on moment.

8. The soft-start method of claim 7, wherein controlling the second output device to delay starting power output at the power-up time comprises:

collecting the output end voltage of the soft starting device;

judging whether the voltage of the output end of the soft starting device is larger than a first threshold value or not;

and if so, controlling the second output device to start power output.

9. The soft-start method of claim 7, wherein controlling the second output device to delay starting power output at the power-up time comprises:

and after a preset first delay time after the power-on time, controlling the second output device to start power output.

10. The soft-start method of claim 7, wherein controlling the first output device to start power output at power-up comprises:

generating the first delay voltage establishment signal according to the power-on signal;

generating a first driving signal according to the first delay voltage establishing signal;

and controlling the output power of the first output device to slowly rise according to the first driving signal.

11. A soft-start power supply apparatus based on a plurality of output devices, comprising the soft-start apparatus according to any one of claims 1 to 6.

12. The power supply device according to claim 11, further comprising:

and the signal source is electrically connected with the driving unit of the soft starting device and provides a power-on signal for the soft starting device.

13. A soft-start chip based on a plurality of output devices, comprising the soft-start apparatus according to any one of claims 1 to 6.