Staggered Power Supply Circuit Startup for DRAM Voltage Stability
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Solution Overview
Problem
In Dynamic Random Access Memory (DRAM) chips, simultaneous start-up of multiple internal power supply circuits generates excessive surge currents, which can pull down external input voltages, leading to unstable output voltages and potential chip failure.
Innovation Solution
A power supply circuit with a control circuit that asynchronously starts different power supply circuits by transmitting first and second enable signals based on a flag signal and external signals, allowing for staggered start times to minimize simultaneous start-ups and reduce surge currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple power supply circuits are started simultaneously, then the chip can initialize all power supply functions quickly, but excessive surge currents are generated that pull down external input voltages and cause instability
Solution Approach 1:
The control circuit activates power supply circuits in a predetermined sequence rather than simultaneously. The first power supply circuit is enabled first to establish a stable voltage baseline, then subsequent power supply circuits are enabled one by one. This preliminary staged activation prevents surge currents from all circuits drawing power at the same moment, thus maintaining voltage stability during chip initialization.
Solution Approach 2:
The power supply initialization process is segmented into multiple sequential stages, with each stage enabling a specific power supply circuit. The control circuit divides the simultaneous start-up into discrete time steps, where each power supply circuit (first-type and second-type) is activated independently at different times based on control signals, preventing the aggregation of surge currents.
2Reliability
If power supply circuits are started in sequence with staggered times, then surge currents are reduced and voltage stability is maintained, but the chip initialization process takes longer
Solution Approach 1:
The control circuit implements periodic enable signals with optimized timing intervals. Rather than using long delays between each power supply activation, the system uses precisely timed periodic pulses that enable each power supply circuit just enough time apart to prevent surge current aggregation. This minimizes the total initialization time while maintaining voltage stability.
Solution Approach 2:
The system dynamically adjusts the timing parameters of enable signals based on the specific requirements of each power supply circuit. By optimizing the duration and interval of enable signals for first-type and second-type power supply circuits, the initialization process achieves the minimum necessary time separation to prevent surge currents, thereby reducing overall initialization time while maintaining reliability.
3Power
If all power supply circuits are enabled at the same time, then the system can provide full power output immediately, but the external input voltage is pulled down causing potential chip failure
Solution Approach 1:
Before enabling subsequent power supply circuits, the control circuit ensures that previous circuits have already established stable voltage output. This preliminary voltage stabilization by the first power supply circuit creates a buffer that prevents the cumulative surge current from later circuits from pulling down the external input voltage, thereby avoiding chip failure while still achieving full power output.
Solution Approach 2:
The control circuit enables power supply circuits in a sequence that creates a cushioning effect. The first power supply circuit acts as a cushioning element that absorbs the initial power demand and stabilizes the voltage before subsequent circuits are enabled. This beforehand cushioning prevents the harmful voltage pull-down effect that would occur if all circuits were enabled simultaneously.
Data Source
AI summary
A power supply circuit and a memory are provided. The power supply circuit includes a voltage source, multiple power supply circuits and a control circuit. The multiple power supply circuits are connected to the voltage source. If the voltage source is effective and the multiple power supply circuits are in an enable state, a voltage of a power supply terminal is pulled up to a preset voltage, and power is supplied to the load units during the pulling up process. A first-type power circuit enters the enable state if a first enable signal is received, and each of second-type power supply circuits enters the enable state if second enable signal is received.