Ldo circuitry and control method

Abstract

The application discloses an LDO circuit system and a control method, wherein the LDO circuit system comprises a controller and an LDO circuit. The LDO circuit comprises at least two comparators, at least two negative feedback loops and an output MOS tube. The output ends of the comparators are electrically connected with the gate of the output MOS tube. The source of the output MOS tube is connected with a power supply. The drain of the output MOS tube is electrically connected with the negative feedback loop. The output ends of the negative feedback loop are respectively and one-to-one connected with the same direction input ends of the comparators. The negative feedback loop comprises a plurality of resistors and controllable switch devices. The resistor parameters of each negative feedback loop are different from each other. The controller is electrically connected with the comparators and the controllable switch devices. According to the LDO circuit system, different static current negative feedback loops can be switched according to the working needs of the load, the transient response performance during the load working is considered, the power consumption in the no-load sleep state is greatly reduced, the battery use time of the electronic equipment is prolonged without affecting the performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of linear power supply, and particularly relates to an LDO circuit system and a control method thereof. BACKGROUND

[0002] With the popularity of portable and wearable electronic products, the power supply mode of electronic products is increasingly adopting battery power supply. Different markets and different categories of electronic products adopt different types of batteries, different power supply voltages and different battery capacities. In particular, for wearable products, the battery capacity is small, and a long standby time is required, which requires the standby power consumption of the system to be extremely low, so that the system can work for a long time without replacing the battery.

[0003] In different varieties of portable and wearable electronic products, battery power supply is adopted, and the power supply voltages required by internal modules are different, and the allowable voltage ranges are also different, so an LDO (Low Dropout Voltage Regulator) is needed to convert the battery voltage into a low operating voltage used by the relevant ASIC.

[0004] For the LDO, the operating performance, especially the transient response performance, is basically in a positive proportional relationship with the power consumption consumed by itself, that is, under normal circumstances, low power consumption will lead to poor operating performance, and the current LDO cannot balance the relatively optimal transient response performance and the relatively low power consumption. SUMMARY

[0005] The purpose of the application is to provide an LDO circuit system that can ensure relatively optimal transient response performance while reducing power consumption to the nA level.

[0006] Another purpose of the application is to provide a control method for controlling the above-mentioned LDO circuit system.

[0007] Technical scheme: The LDO circuit system disclosed by the application comprises a controller and an LDO circuit, wherein the LDO circuit comprises at least two comparators, at least two negative feedback loops and an output MOS tube, the output ends of the comparators are electrically connected with the gate electrodes of the output MOS tube, the source electrode of the output MOS tube is connected with a power supply, the drain electrode of the output MOS tube is electrically connected with the negative feedback loop, the output ends of the negative feedback loop are respectively and one-to-one connected with the same direction input ends of the comparators, the negative feedback loop comprises a plurality of resistors and controllable switching devices, the resistor parameters of each negative feedback loop are different from each other, and the controller is electrically connected with the comparators and the controllable switching devices.

[0008] Furthermore, there are two comparators and two negative feedback loops. The first negative feedback loop and the second negative feedback loop are electrically connected to the non-inverting input terminals of the first comparator and the second comparator, respectively. The static current of the first negative feedback loop is less than that of the second negative feedback loop when it is working.

[0009] Furthermore, the controller includes an output current detection module, an output voltage monitoring module, multiple timers, and a state control module. The output current detection module is used to detect the load current output by the LDO circuit, the output voltage monitoring module is used to monitor the load voltage output by the LDO circuit, the multiple timers are used to time the duration of the power input and the load current within different threshold ranges, and the state control module is used to output control signals according to the load current and the state of the timers to control the comparator and the controllable switching device to work or stop.

[0010] The control method for the LDO circuit system described in this invention includes at least two operating states: a low-power state and a medium-power state. In the low-power state, a first load circuit with a lower quiescent current operates, and in the medium-power state, a second load circuit with a higher quiescent current operates. The switching method is as follows: When the LDO circuit system is first powered on, it enters the medium-power state. After a first time interval, it begins to continuously monitor the load current output by the LDO circuit system. When the LDO circuit system is in the medium-power state, and the load current remains below a first threshold for a period longer than a second time interval, it enters the low-power state and begins to continuously monitor the load voltage output by the LDO circuit system. When the LDO circuit system is in the low-power state, and the load current is greater than a second threshold or the load voltage is undervoltage, it enters the medium-power state.

[0011] Furthermore, the first threshold is 0.5mA.

[0012] Furthermore, the second threshold is 1.0 mA.

[0013] Beneficial effects: Compared with the prior art, the present invention has the following advantages: By setting up negative feedback loops with different parameters and switching the working negative feedback loops according to the load state, the negative feedback loop with higher static current is allowed to work when transient response performance is required, and the negative feedback loop with lower static current is switched to work when transient response performance is not required and the load current is small and stable, thus maintaining low power consumption. This balances transient response performance with power consumption reduction, and extends the battery life of electronic devices without affecting performance. Attached Figure Description

[0014] Figure 1 The circuit diagram of the negative feedback loop of the LDO circuit system in an embodiment of the present invention is shown.

[0015] Figure 2 This is a system block diagram of the controller of the LDO circuit system according to an embodiment of the present invention;

[0016] Figure 3 The diagram shows the no-load power-on simulation results of the LDO circuit system according to an embodiment of the present invention. Detailed Implementation

[0017] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0018] Reference Figure 1 According to an embodiment of the present invention, an LDO circuit system includes a controller and an LDO circuit. The LDO circuit includes an output MOSFET, at least two comparators, and at least two corresponding negative feedback loops. The output terminal of each comparator is connected to the gate of the output MOSFET, the source of the output MOSFET is connected to a DC power supply, and the drain of the MOSFET is connected to the non-inverting input terminal of each comparator through the negative feedback loops to form multiple negative feedback loops. Each negative feedback loop consists of multiple voltage-dividing resistors, and the resistance parameters of each negative feedback loop are different, resulting in different quiescent currents during operation. A controllable switching device is connected in series in each negative feedback loop. The controllable switching device and the comparators are electrically connected to and controlled by the controller. The controller can control whether the comparators operate and control the on / off state of the controllable switching device to connect load loops with different quiescent currents to the system.

[0019] The above technical solution, by setting up negative feedback loops with different parameters and switching them according to the load conditions, allows the negative feedback loop with higher quiescent current to operate when the load current is high, the load is in an active state, and good transient response performance is required, ensuring that the LDO circuit can quickly respond to load demands. When the load current remains low, i.e., the load is in a dormant state, the negative feedback loop with lower quiescent current is switched on to reduce power consumption and thus extend battery life. This LDO circuit system can balance transient response performance with reduced power consumption.

[0020] Reference Figure 2 The controller includes an output current detection module, an output voltage monitoring module, multiple timers, and a state control module. The output current detection module detects the load current output by the LDO circuit, the output voltage monitoring module monitors the load voltage output by the LDO circuit, the timers time the duration for which the power input and load current are within different threshold ranges, and the state control module outputs control signals based on the load current and the state of the timers to control the operation of the comparator and controllable switching devices, thereby achieving the switching of the negative feedback loop.

[0021] Reference Figure 1 and Figure 2In this embodiment, two comparators and two negative feedback loops are included. The first comparator, voltage divider resistors R1 and R2, and the output MOSFET form a low-power negative feedback system with a quiescent current of approximately 25nA. The second comparator, voltage divider resistors R3 and R4, and the output MOSFET form a medium-power negative feedback system with a quiescent current of approximately 25μA. A thyristor is used as the controllable switching device. When the state control module outputs a high-level control signal CT, the second comparator, voltage divider resistors R3 and R4 operate, and the system is in a medium-power state with good transient response performance, allowing for rapid load response. When the state control module outputs a low-level control signal CT, the first comparator, voltage divider resistors R1 and R2 operate, and the system is in a low-power state with power consumption significantly lower than the medium-power state. It is understood that in practice, negative feedback loops with higher or lower quiescent currents can be designed according to load requirements to meet different load operating states.

[0022] Reference Figure 2 In practice, the controller switches the negative feedback loop by monitoring changes in load current and voltage. During system startup, the load is typically under heavy load, so a negative feedback loop with a larger quiescent current is selected during startup; in this embodiment, a medium power consumption state is used. After a certain startup time, once the load stabilizes, the controller begins monitoring the load current output from the LDO circuit to the load. If the current remains below the current threshold range for a certain period, the controller switches to a negative feedback loop with a lower quiescent current. Conversely, if the current jumps above the current threshold range or undervoltage is detected, the controller switches to a negative feedback loop with a higher quiescent current. In practice, to prevent system oscillation, a certain hysteresis is required between the thresholds for switching to a higher-current negative feedback loop and a lower-current negative feedback loop.

[0023] In this embodiment, the switching rules between the low-power state and the medium-power state are as follows:

[0024] When the LDO circuit system is in the medium power consumption state and the load current is less than 0.5mA for a longer period than the second time, it enters the low power consumption state and begins to continuously monitor the load voltage output by the LDO circuit system.

[0025] When the LDO circuit system is in a low-power state, and the load current is greater than 1.0mA or the load voltage is undervoltage, it enters a medium-power state.

[0026] The no-load power-on simulation results of the LDO circuit system in this embodiment are as follows: Figure 3 As shown, under no-load startup, the output powers on quickly and stabilizes. After about 100ms, the static current stabilizes and decreases to about 27.7nA. The transient response is fast and the power consumption is low after stabilization.

Claims

1. An LDO circuit system, characterized in that, The system includes a controller and an LDO circuit. The LDO circuit comprises at least two comparators, at least two negative feedback loops, and an output MOSFET. The output terminals of each comparator are electrically connected to the gate of the output MOSFET. The source of the output MOSFET is connected to a power supply, and the drain of the output MOSFET is electrically connected to the negative feedback loop. The output terminals of each negative feedback loop are connected to the non-inverting input of the comparators. Each negative feedback loop includes several resistors and controllable switches. The resistance parameters of each negative feedback loop are different, resulting in different quiescent currents during operation. The controller is connected to the comparators and the controllable switches. The devices are electrically connected. The controller includes an output current detection module, an output voltage monitoring module, multiple timers, and a state control module. The output current detection module is used to detect the load current output by the LDO circuit. The output voltage monitoring module is used to monitor the load voltage output by the LDO circuit. The multiple timers are used to time the duration of the power input and the load current within different threshold ranges. The state control module is used to output control signals according to the load current and the state of the timers to control the comparator and the controllable switching device to work or stop, and to connect negative feedback loops with different quiescent currents to the LDO circuit system.

2. The LDO circuit system according to claim 1, characterized in that, The number of comparators is two, and the number of negative feedback loops is two. The first negative feedback loop and the second negative feedback loop are electrically connected to the non-inverting input terminals of the first comparator and the second comparator, respectively. The static current of the first negative feedback loop is less than that of the second negative feedback loop when it is working.

3. A control method for an LDO circuit system according to any one of claims 1 to 2, characterized in that, It includes at least two operating states: a low-power state and a medium-power state. In the low-power state, the first load circuit with a lower static current operates, and in the medium-power state, the second load circuit with a higher static current operates. The switching method is as follows: When the LDO circuit system is first powered on, it enters a medium power consumption state. After the first period, it begins to continuously monitor the load current output by the LDO circuit system. When the LDO circuit system is in a medium power consumption state, and the load current is continuously less than the first threshold for a longer period than the second time, it enters a low power consumption state and begins to continuously monitor the load voltage output by the LDO circuit system. When the LDO circuit system is in a low-power state, and the load current is greater than the second threshold or the load voltage is undervoltage, it enters a medium-power state.

4. The control method for the LDO circuit system according to claim 3, characterized in that, The first threshold is 0.5mA.

5. The control method for the LDO circuit system according to claim 3, characterized in that, The second threshold is 1.0 mA.

Images