partially solved issue with random modulator and ADC clock stopping at the end of ЛЧМ. Done: when we want to stop clocks -- enable IRQ on sloewr clock (TIM11). In IRQ switches TIM4, TIM11 to one-pulse mode, disables IRQ. When we starting these timers th next time -- we resets their counters, one-pulse mode disables.

Inc/stm32f7xx_it.h

@@ -57,6 +57,7 @@ void PendSV_Handler(void);
 void SysTick_Handler(void);
 void ADC_IRQHandler(void);
 void TIM1_UP_TIM10_IRQHandler(void);
+void TIM1_TRG_COM_TIM11_IRQHandler(void);
 void TIM2_IRQHandler(void);
 void USART1_IRQHandler(void);
 void TIM8_UP_TIM13_IRQHandler(void);